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Brian Norris 999b3d17af drm/rockchip: vop: Leave vblank enabled in self-refresh 
commit 2bdba9d4a3 upstream.

If we disable vblank when entering self-refresh, vblank APIs (like
DRM_IOCTL_WAIT_VBLANK) no longer work. But user space is not aware when
we enter self-refresh, so this appears to be an API violation -- that
DRM_IOCTL_WAIT_VBLANK fails with EINVAL whenever the display is idle and
enters self-refresh.

The downstream driver used by many of these systems never used to
disable vblank for PSR, and in fact, even upstream, we didn't do that
until radically redesigning the state machine in commit 6c836d965b
("drm/rockchip: Use the helpers for PSR").

Thus, it seems like a reasonable API fix to simply restore that
behavior, and leave vblank enabled.

Note that this appears to potentially unbalance the
drm_crtc_vblank_{off,on}() calls in some cases, but:
(a) drm_crtc_vblank_on() documents this as OK and
(b) if I do the naive balancing, I find state machine issues such that
    we're not in sync properly; so it's easier to take advantage of (a).

This issue was exposed by IGT's kms_vblank tests, and reported by
KernelCI. The bug has been around a while (longer than KernelCI
noticed), but was only exposed once self-refresh was bugfixed more
recently, and so KernelCI could properly test it. Some other notes in:

  https://lore.kernel.org/dri-devel/Y6OCg9BPnJvimQLT@google.com/
  Re: renesas/master bisection: igt-kms-rockchip.kms_vblank.pipe-A-wait-forked on rk3399-gru-kevin

== Backporting notes: ==

Marking as 'Fixes' commit 6c836d965b ("drm/rockchip: Use the helpers
for PSR"), but it probably depends on commit bed030a49f
("drm/rockchip: Don't fully disable vop on self refresh") as well.

We also need the previous patch ("drm/atomic: Allow vblank-enabled +
self-refresh "disable""), of course.

v3:
 * no update

v2:
 * skip unnecessary lock/unlock

Fixes: 6c836d965b ("drm/rockchip: Use the helpers for PSR")
Cc: <stable@vger.kernel.org>
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Link: https://lore.kernel.org/dri-devel/Y5itf0+yNIQa6fU4@sirena.org.uk/
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230109171809.v3.2.Ic07cba4ab9a7bd3618a9e4258b8f92ea7d10ae5a@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2023-07-23 13:54:02 +02:00
arch arm64: dts: ti: k3-j721s2: Fix wkup pinmux range 2023-07-23 13:53:58 +02:00
block blk-crypto: use dynamic lock class for blk_crypto_profile::lock 2023-07-23 13:53:39 +02:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: jitter - correct health test during initialization 2023-07-19 16:36:19 +02:00
Documentation fs: Lock moved directories 2023-07-19 16:36:55 +02:00
drivers
fs fs: dlm: fix missing pending to false 2023-07-23 13:54:02 +02:00
include kasan: use internal prototypes matching gcc-13 builtins 2023-07-23 13:53:54 +02:00
init kbuild: Fix CFI failures with GCOV 2023-07-19 16:36:23 +02:00
io_uring io_uring: Use io_schedule* in cqring wait 2023-07-19 16:37:03 +02:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel tracing/user_events: Fix incorrect return value for writing operation when events are disabled 2023-07-23 13:53:54 +02:00
lib lib: dhry: fix sleeping allocations inside non-preemptable section 2023-07-19 16:36:50 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/mmap: Fix error return in do_vmi_align_munmap() 2023-07-23 13:53:57 +02:00
net net/sched: sch_qfq: account for stab overhead in qfq_enqueue 2023-07-23 13:53:49 +02:00
rust Rust changes for v6.4 2023-04-30 11:20:22 -07:00
samples samples/bpf: xdp1 and xdp2 reduce XDPBUFSIZE to 60 2023-07-19 16:35:25 +02:00
scripts kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGS 2023-07-19 16:37:00 +02:00
security security/integrity: fix pointer to ESL data and its size on pseries 2023-07-23 13:53:34 +02:00
sound ASoC: mediatek: mt8173: Fix snd_soc_component_initialize error path 2023-07-19 16:36:58 +02:00
tools wireguard: netlink: send staged packets when setting initial private key 2023-07-19 16:37:02 +02:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt KVM: Avoid illegal stage2 mapping on invalid memory slot 2023-06-22 15:14:57 -04:00
.clang-format cxl for v6.4 2023-04-30 11:51:51 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore linux-kselftest-kunit-6.4-rc1 2023-04-24 12:31:32 -07:00
.mailmap mailmap: add entries for Ben Dooks 2023-06-19 13:19:35 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: sctp: move Neil to CREDITS 2023-05-12 08:51:32 +01:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Networking fixes for 6.4-rc8, including fixes from ipsec, bpf, 2023-06-22 17:59:51 -07:00
Makefile kbuild: make modules_install copy modules.builtin(.modinfo) 2023-07-23 13:53:51 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.