Precalculated hash for empty message are now present in hash headers.
This patch just use them.
Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Add Colibri standard pinmux for FlexCAN controller instances. CAN
is not a standard Colibri feature, but the datasheet predefines
pins which provide CAN (compatible across some modules). Hence,
add the pinmux on module level.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Precalculated hash for empty message are now present in hash headers.
This patch just use them.
Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
No functional change, just moving the node to the place where it
belongs according to its unit address.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This allows for consistent numbering of the IPU output and
input ports.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This has been moved to the reg property where it belongs for quite some
time. The range has been unused by the kernel since then and with kernel
4.4 it's flagged as an unparsable range, as it does not comply to the
PCI ranges DT binding. Fix this by removing the superfluous range.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Audio IP need the spba clock, but original clock name "dma" is not
accurate, so change it to name "spba". The audio driver has been
using the new name "spba", the binding document has been updated.
Signed-off-by: Shengjiu Wang <shengjiu.wang@freescale.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Alison Wang <b18965@freescale.com>
Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Jianwei Wang <jianwei.wang.chn@gmail.com>
Signed-off-by: Meng Yi <b56799@freescale.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Alison Wang <b18965@freescale.com>
Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Jianwei Wang <jianwei.wang.chn@gmail.com>
Signed-off-by: Meng Yi <b56799@freescale.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
As on i.MX7D, we using a virtual arm clk for CPU frequency
scaling, so correct the clocks info used by the cpufreq driver.
Signed-off-by: Bai Ping <b51503@freescale.com>
Acked-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Some crypto drivers cannot process empty data message and return a
precalculated hash for md5/sha1/sha224/sha256.
This patch add thoses precalculated hash in include/crypto.
Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Change the timeout condition since the times value would be -1 after
running MAX_RETRY_TIMES.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Yang Pingchao <pingchao.yang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
AE CTX bits should be 8-15 in CTX_ENABLES, so the mask
value 0xff should be left shifted 0x8.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Yang Pingchao <pingchao.yang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Avoid the s390 compile "warning: 'pkcs1pad_encrypt_sign_complete'
uses dynamic stack allocation" reported by kbuild test robot. Don't
use a flat zero-filled buffer, instead zero the contents of the SGL.
Signed-off-by: Andrew Zaborowski <andrew.zaborowski@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This addes support for SPI available on an off-board connector available on
some models of the GW52xx.
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Ventana boards have an off-board connector with signals that can be pinmuxed
as either GPIO or PWM. This patch adds pwm device-tree nodes in the disabled
state which the bootloader can decide to enable based on bootloader config.
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Minimal Cortex-M4 device tree to boot Linux to shell. M4 is booted via
Cortex-A5 running Linux using Stefan Agner's <stefan@agner.ch> "m4boot"
utility.
Signed-off-by: Afzal Mohammed <afzal.mohd.ma@gmail.com>
Acked-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Extend the existing Vybrid DSPI devicetree implementation to also
describe the dspi2 and dspi3 functional blocks.
Signed-off-by: Cory Tusar <cory.tusar@pid1solutions.com>
Acked-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This, together with the corresponding patch to pwm-imx.c, allows to order the
pwm devices correctly.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
imx6qdl.dtsi uses compatibles "fsl,imx6q-gpt", "fsl,imx31-gpt".
imx6dl.dtsi uses compatibles "fsl,imx6dl-gpt", "fsl,imx6q-gpt" since
commit
4e415ed814 (ARM: dts: imx6dl: add imx6dl gpt specific compatible string)
If imx6dl would be compatible with imx6q-gpt it would also have to be
compatible with imx31-gpt which is currently missing.
Based on the above mentioned patch I assume imx6q-gpt and imx6dl-gpt are
not compatible. So imx6q-gpt should be removed as compatible.
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Currently it is not possible to have HDMI and LVDS working simultaneously,
because both ports try to use PLL5.
Move the LVDS clock parent to PLL3_USB_OTG, so that HDMI and LVDS can be
driven from independent sources.
With this change the LDB pixel clock goes to 68.57 MHz, which is still
within the valid range for the displays supported by the Ventana boards.
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
The GW54xx PMIC swbst regulator is used for LVDS power, CANbus xceiver
and HDMI DDC and is enabled by the bootloader. Set the regulator to
always-on so that Linux doesn't turn it off thinking its not needed.
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This patch adds some values that are needed for an out-of-tree device
tree I'm currently working with.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Specify the 'adck-max-frequency' property in the adc nodes.
According to Documentation/devicetree/bindings/iio/adc/vf610-adc.txt
this is a recommended property.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
It can improve the USB performance when choosing larger
burst size at some systems (bus size is larger), there is
no side effect if this burst size is larger than bus size.
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
After setting ahb burst configuration as 0, we can increase tx/rx
burst size, it will improve the USB performance
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This patch replaces uses of ablkcipher with the new skcipher
interface.
Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: <smueller@chronox.de>
The TLV format for little endian structures is actually 4 byte aligned
copy. To this end, we need to add an additional __aligned(4) marker
along with __packed to ensure that these structures are actually 4 byte
aligned and packed correctly. Use of just __packed will not work as this
will result in 1byte alignment which is incorrect. Add a comment
explaining the reasoning behind why these structures need the special
treatment.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cleans up checkpatch GLOBAL_INITIALIZERS error
Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
According to commit 2503a5ecd8
"ARM: 6201/1: RealView: Do not use outer_sync() on ARM11MPCore
boards with L220" Some PB11MPCore RealView core tiles have broken
outer_sync.
We got rid of the custom barriers from the machine by disabling
outer sync, but that was just for the boardfile case. We have
to be able to do the same in the device tree case.
Since __l2c_init() is cloning and copying the L2C vtable,
we pass an argument to this function to optionally numb
the outer sync operation if desired, before initializing
the cache.
After this we can set up the cache correctly on the RealView
PB11MPCore. This was tested on a PB11MPCore known to have the
issue. Before this, spurious crashes would occur if we try to
set up the cache properly, after this it boots rock solid.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: devicetree@vger.kernel.org
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Having IPI_CPU_BACKTRACE as SGI15 may not work if the kernel is
running in non-secure mode and that the secure firmware has
decided to follow ARM's recommendations that SGI8-15 should
be reserved for secure purpose.
Now that we are "only" using SGI0-6, change IPI_CPU_BACKTRACE
to use SGI7, which makes it more likely to work.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Since 9a46ad6d6d ("smp: make smp_call_function_many() use logic
similar to smp_call_function_single()"), the core IPI handling
has been simplified, and generic_smp_call_function_interrupt is
now the same as generic_smp_call_function_single_interrupt.
This means that one of IPI_CALL_FUNC and IPI_CALL_FUNC_SINGLE has
become redundant. We can then safely drop IPI_CALL_FUNC_SINGLE,
and use only IPI_CALL_FUNC.
This has the advantage of reducing the number of SGI IDs we're using
(a fairly scarse resource).
Tested on a dual A7 board.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The suspend() hook in the cpuidle_ops struct is always called on
the cpu entering idle, which means that the cpu parameter passed
to the suspend hook always corresponds to the local cpu, making
it somewhat redundant.
This patch removes the logical cpu parameter from the ARM
cpuidle_ops.suspend hook and updates all the existing kernel
implementations to reflect this change.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Lina Iyer <lina.iyer@linaro.org>
Tested-by: Lina Iyer <lina.iyer@linaro.org>
Tested-by: Jisheng Zhang <jszhang@marvell.com> [psci]
Cc: Lina Iyer <lina.iyer@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
There was a silent conflict between
commit 0a87871626
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Thu Oct 15 14:23:01 2015 +0200
drm/i915: restore ggtt double-bind avoidance
and
commit 5bab6f60cb
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri Oct 23 18:43:32 2015 +0100
drm/i915: Serialise updates to GGTT with access through GGTT on Braswell
thankfully caught by the extra WARN safegaurd in 0a878716. Since we now
override the GGTT insert_pages callback when installing the aliasing
ppgtt, we assert that the callback is the original ggtt routine.
However, on Braswell we now use a different insertion routine to
serialise access through the GGTT with updating the PTE and hence the
conflict. To avoid the conflict, move the custom insertion routine for
Braswell down a level.
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1447859979-20107-1-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: drm-intel-fixes@lists.freedesktop.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit c140330b5e)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Commit ebb5e78cc6 ("MIPS: Initial implementation of a VDSO") introduced a
build error.
For MIPS VDSO to be compiled it requires binutils version 2.25 or above but
the check in the Makefile had inverted logic causing it to be compiled in if
binutils is below 2.25.
This fixes the following compilation error:
CC arch/mips/vdso/gettimeofday.o
/tmp/ccsExcUd.s: Assembler messages:
/tmp/ccsExcUd.s:62: Error: can't resolve `_start' {*UND* section} - `L0' {.text section}
/tmp/ccsExcUd.s:467: Error: can't resolve `_start' {*UND* section} - `L0' {.text section}
make[2]: *** [arch/mips/vdso/gettimeofday.o] Error 1
make[1]: *** [arch/mips/vdso] Error 2
make: *** [arch/mips] Error 2
[ralf@linux-mips: Fixed Sergei's complaint on the formatting of the
cited commit and generally reformatted the log message.]
Signed-off-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: alex@alex-smith.me.uk
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11745/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Commit 977e043d5e ("MIPS: kernel: cps-vec: Replace mips32r2 ISA level
with mips64r2") leads to .set mips64r2 directives being present in 32
bit (ie. CONFIG_32BIT=y) kernels. This is incorrect & leads to MIPS64
instructions being emitted by the assembler when expanding
pseudo-instructions. For example the "move" instruction can legitimately
be expanded to a "daddu". This causes problems when the kernel is run on
a MIPS32 CPU, as CONFIG_32BIT kernels of course often are...
Fix this by dropping the .set <ISA> directives entirely now that Kconfig
should be ensuring that kernels including this code are built with a
suitable -march= compiler flag.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: <stable@vger.kernel.org> # 3.16+
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10869/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The total delay of HDMI hotplug detecting with 30ms have already
been split into a resolution of 3 retries of 10ms each, for the worst
cases. But it still suffered from only waiting 10ms at most in
intel_hdmi_detect(). This patch corrects it by reading hotplug status
with 4 times at most for 30ms delay.
v2:
- straight up to loop execution for more clear in code readability
- mdelay will replace with msleep by Daniel's new patch
drm/i915: mdelay(10) considered harmful
- suggest to re-evaluate try times for being compatible to old HDMI monitor
Reviewed-by: Cooper Chiou <cooper.chiou@intel.com>
Tested-by: Gary Wang <gary.c.wang@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Gavin Hindman <gavin.hindman@intel.com>
Cc: Sonika Jindal <sonika.jindal@intel.com>
Cc: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Gary Wang <gary.c.wang@intel.com>
[danvet: fixup conflict with s/mdelay/msleep/ patch.]
Cc: drm-intel-fixes@lists.freedesktop.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit 61fb3980dd)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
I missed this myself when reviewing
commit 237ed86c69
Author: Sonika Jindal <sonika.jindal@intel.com>
Date: Tue Sep 15 09:44:20 2015 +0530
drm/i915: Check live status before reading edid
Long sleeps like this really shouldn't waste cpu cycles spinning.
Cc: Sonika Jindal <sonika.jindal@intel.com>
Cc: "Wang, Gary C" <gary.c.wang@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1449859455-32609-1-git-send-email-daniel.vetter@ffwll.ch
Reviewed-by: Sonika Jindal <sonika.jindal@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit 71a199bacb)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
The vma may have been rebound between the last time the cursor was
enabled and now, so skipping the cursor gtt offset deduction is not
safe unless we would also reset cursor_bo to NULL when disabling the
cursor. Just thow cursor_bo to the bin instead since it's lost all
other uses thanks to universal plane support.
Chris pointed out that cursor updates are currently too slow
via universal planes that micro optimizations like these wouldn't
even help.
v2: Add a note about futility of micro optimizations (Chris)
Cc: drm-intel-fixes@lists.freedesktop.org
References: http://lists.freedesktop.org/archives/intel-gfx/2015-December/082976.html
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450107302-17171-1-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
(cherry picked from commit 1264859d64)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
__clear_user() (and clear_user() which uses it), always access the user
mode address space, which results in EVA store instructions when EVA is
enabled even if the current user address limit is KERNEL_DS.
Fix this by adding a new symbol __bzero_kernel for the normal kernel
address space bzero in EVA mode, and call that from __clear_user() if
eva_kernel_access().
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10844/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Turns out CHV pipe C was glued on somewhat poorly, and there's something
wrong with the cursor. If the cursor straddles the left screen edge,
and is then moved away from the edge or disabled, the pipe will often
underrun. If enough underruns are triggered quickly enough the pipe
will fall over and die (it just scans out a solid color and reports
a constant underrun). We need to turn the disp2d power well off and
on again to recover the pipe.
None of that is very nice for the user, so let's just refuse to place
the cursor in the compromised position. The ddx appears to fall back
to swcursor when the ioctl returns an error, so theoretically there's
no loss of functionality for the user (discounting swcursor bugs).
I suppose most cursors images actually have the hotspot not exactly
at 0,0 so under typical conditions the fallback will in fact kick in
as soon as the cursor touches the left edge of the screen.
Any atomic compositor should anyway be prepared to fall back to
GPU composition when things don't work out, so there should be no
problem with those.
Other things that I tried to solve this include flipping all
display related clock gating knobs I could find, increasing the
minimum gtt alignment all the way up to 512k. I also tried to see
if there are more specific screen coordinates that hit the bug, but
the findings were somewhat inconclusive. Sometimes the failures
happen almost across the whole left edge, sometimes more at the very
top and around the bottom half. I wasn't able to find any real pattern
to these variations, so it seems our only choice is to just refuse
to straddle the left screen edge at all.
Cc: stable@vger.kernel.org
Cc: Jason Plum <max@warheads.net>
Testcase: igt/kms_chv_cursor_fail
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92826
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450459479-16286-1-git-send-email-ville.syrjala@linux.intel.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit b29ec92c4f)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Limit busywaiting only to the request currently being processed by the
GPU. If the request is not currently being processed by the GPU, there
is a very low likelihood of it being completed within the 2 microsecond
spin timeout and so we will just be wasting CPU cycles.
v2: Check for logical inversion when rebasing - we were incorrectly
checking for this request being active, and instead busywaiting for
when the GPU was not yet processing the request of interest.
v3: Try another colour for the seqno names.
v4: Another colour for the function names.
v5: Remove the forced coherency when checking for the active request. On
reflection and plenty of recent experimentation, the issue is not a
cache coherency problem - but an irq/seqno ordering problem (timing issue).
Here, we do not need the w/a to force ordering of the read with an
interrupt.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: "Rogozhkin, Dmitry V" <dmitry.v.rogozhkin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Eero Tamminen <eero.t.tamminen@intel.com>
Cc: "Rantala, Valtteri" <valtteri.rantala@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449833608-22125-4-git-send-email-chris@chris-wilson.co.uk
(cherry picked from commit 821485dc2a)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
When waiting for high frequency requests, the finite amount of time
required to set up the irq and wait upon it limits the response rate. By
busywaiting on the request completion for a short while we can service
the high frequency waits as quick as possible. However, if it is a slow
request, we want to sleep as quickly as possible. The tradeoff between
waiting and sleeping is roughly the time it takes to sleep on a request,
on the order of a microsecond. Based on measurements of synchronous
workloads from across big core and little atom, I have set the limit for
busywaiting as 10 microseconds. In most of the synchronous cases, we can
reduce the limit down to as little as 2 miscroseconds, but that leaves
quite a few test cases regressing by factors of 3 and more.
The code currently uses the jiffie clock, but that is far too coarse (on
the order of 10 milliseconds) and results in poor interactivity as the
CPU ends up being hogged by slow requests. To get microsecond resolution
we need to use a high resolution timer. The cheapest of which is polling
local_clock(), but that is only valid on the same CPU. If we switch CPUs
because the task was preempted, we can also use that as an indicator that
the system is too busy to waste cycles on spinning and we should sleep
instead.
__i915_spin_request was introduced in
commit 2def4ad99b [v4.2]
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue Apr 7 16:20:41 2015 +0100
drm/i915: Optimistically spin for the request completion
v2: Drop full u64 for unsigned long - the timer is 32bit wraparound safe,
so we can use native register sizes on smaller architectures. Mention
the approximate microseconds units for elapsed time and add some extra
comments describing the reason for busywaiting.
v3: Raise the limit to 10us
v4: Now 5us.
Reported-by: Jens Axboe <axboe@kernel.dk>
Link: https://lkml.org/lkml/2015/11/12/621
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: "Rogozhkin, Dmitry V" <dmitry.v.rogozhkin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Eero Tamminen <eero.t.tamminen@intel.com>
Cc: "Rantala, Valtteri" <valtteri.rantala@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449833608-22125-3-git-send-email-chris@chris-wilson.co.uk
(cherry picked from commit ca5b721e23)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
