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Sean Paul 28291b0124 drm/msm: Set dma maximum segment size for mdss [ Upstream commit `db735fc403` ] Turning on CONFIG_DMA_API_DEBUG_SG results in the following error: [ 12.078665] msm ae00000.mdss: DMA-API: mapping sg segment longer than device claims to support [len=3526656] [max=65536] [ 12.089870] WARNING: CPU: 6 PID: 334 at /mnt/host/source/src/third_party/kernel/v4.19/kernel/dma/debug.c:1301 debug_dma_map_sg+0x1dc/0x318 [ 12.102655] Modules linked in: joydev [ 12.106442] CPU: 6 PID: 334 Comm: frecon Not tainted 4.19.0 #2 [ 12.112450] Hardware name: Google Cheza (rev3+) (DT) [ 12.117566] pstate: 60400009 (nZCv daif +PAN -UAO) [ 12.122506] pc : debug_dma_map_sg+0x1dc/0x318 [ 12.126995] lr : debug_dma_map_sg+0x1dc/0x318 [ 12.131487] sp : ffffff800cc3ba80 [ 12.134913] x29: ffffff800cc3ba80 x28: 0000000000000000 [ 12.140395] x27: 0000000000000004 x26: 0000000000000004 [ 12.145868] x25: ffffff8008e55b18 x24: 0000000000000000 [ 12.151337] x23: 00000000ffffffff x22: ffffff800921c000 [ 12.156809] x21: ffffffc0fa75b080 x20: ffffffc0f7195090 [ 12.162280] x19: ffffffc0f1c53280 x18: 0000000000000000 [ 12.167749] x17: 0000000000000000 x16: 0000000000000000 [ 12.173218] x15: 0000000000000000 x14: 0720072007200720 [ 12.178689] x13: 0720072007200720 x12: 0720072007200720 [ 12.184161] x11: 0720072007200720 x10: 0720072007200720 [ 12.189641] x9 : ffffffc0f1fc6b60 x8 : 0000000000000000 [ 12.195110] x7 : ffffff8008132ce0 x6 : 0000000000000000 [ 12.200585] x5 : 0000000000000000 x4 : ffffff8008134734 [ 12.206058] x3 : ffffff800cc3b830 x2 : ffffffc0f1fc6240 [ 12.211532] x1 : 25045a74f48a7400 x0 : 25045a74f48a7400 [ 12.217006] Call trace: [ 12.219535] debug_dma_map_sg+0x1dc/0x318 [ 12.223671] get_pages+0x19c/0x20c [ 12.227177] msm_gem_fault+0x64/0xfc [ 12.230874] __do_fault+0x3c/0x140 [ 12.234383] __handle_mm_fault+0x70c/0xdb8 [ 12.238603] handle_mm_fault+0xac/0xc4 [ 12.242473] do_page_fault+0x1bc/0x3d4 [ 12.246342] do_translation_fault+0x54/0x88 [ 12.250652] do_mem_abort+0x60/0xf0 [ 12.254250] el0_da+0x20/0x24 [ 12.257317] irq event stamp: 67260 [ 12.260828] hardirqs last enabled at (67259): [<ffffff8008132d0c>] console_unlock+0x214/0x608 [ 12.269693] hardirqs last disabled at (67260): [<ffffff8008080e0c>] do_debug_exception+0x5c/0x178 [ 12.278820] softirqs last enabled at (67256): [<ffffff8008081664>] __do_softirq+0x4d4/0x520 [ 12.287510] softirqs last disabled at (67249): [<ffffff80080be574>] irq_exit+0xa8/0x100 [ 12.295742] ---[ end trace e63cfc40c313ffab ]--- The root of the problem is that the default segment size for sgt is (UINT_MAX & PAGE_MASK), and the default segment size for device dma is 64K. As such, if you compare the 2, you would deduce that the sg segment will overflow the device's capacity. In reality, the hardware can accommodate the larger sg segments, it's just not initializing its max segment properly. This patch initializes the max segment size for the mdss device, which gets rid of that pesky warning. Reported-by: Stephen Boyd <swboyd@chromium.org> Tested-by: Stephen Boyd <swboyd@chromium.org> Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> Reviewed-by: Rob Clark <robdclark@gmail.com> Signed-off-by: Sean Paul <seanpaul@chromium.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20200121111813.REPOST.1.I92c66a35fb13f368095b05287bdabdbe88ca6922@changeid Signed-off-by: Sasha Levin <sashal@kernel.org>		History 2020-03-05 16:45:04 +01:00
arch	s390/mm: Explicitly compare PAGE_DEFAULT_KEY against zero in storage_key_init_range	2020-02-28 17:23:45 +01:00
block	block, bfq: do not plug I/O for bfq_queues with no proc refs	2020-02-24 08:38:09 +01:00
certs	certs: Add wrapper function to check blacklisted binary hash	2019-11-12 12:25:50 +11:00
crypto	crypto: rename sm3-256 to sm3 in hash_algo_name	2020-02-28 17:23:43 +01:00
Documentation	mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()	2020-02-28 17:23:37 +01:00
drivers	drm/msm: Set dma maximum segment size for mdss	2020-03-05 16:45:04 +01:00
fs	io_uring: fix __io_iopoll_check deadlock in io_sq_thread	2020-02-28 17:23:43 +01:00
include	net: export netdev_next_lower_dev_rcu()	2020-03-05 16:45:02 +01:00
init	Revert "um: Enable CONFIG_CONSTRUCTORS"	2020-02-01 09:33:00 +00:00
ipc	Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()"	2020-02-28 17:23:36 +01:00
kernel	dma-direct: relax addressability checks in dma_direct_supported	2020-02-28 17:23:44 +01:00
lib	crypto: chacha20poly1305 - prevent integer overflow on large input	2020-02-28 17:23:40 +01:00
LICENSES	LICENSES: Rename other to deprecated	2019-05-03 06:34:32 -06:00
mm	mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()	2020-02-28 17:23:37 +01:00
net	net: rtnetlink: fix bugs in rtnl_alt_ifname()	2020-03-05 16:45:03 +01:00
samples	samples/bpf: Set -fno-stack-protector when building BPF programs	2020-02-24 08:38:15 +01:00
scripts	scripts/get_maintainer.pl: deprioritize old Fixes: addresses	2020-02-28 17:23:43 +01:00
security	selinux: ensure we cleanup the internal AVC counters on error in avc_update()	2020-02-24 08:38:19 +01:00
sound	ASoC: SOF: Intel: hda: Add iDisp4 DAI	2020-02-28 17:23:45 +01:00
tools	ipv6: Fix route replacement with dev-only route	2020-03-05 16:45:03 +01:00
usr	gen_initramfs_list.sh: fix 'bad variable name' error	2020-01-04 00:00:48 +09:00
virt	KVM: arm64: Treat emulated TVAL TimerValue as a signed 32-bit integer	2020-02-14 16:53:04 -05:00
.clang-format	clang-format: Update with the latest for_each macro list	2019-08-31 10:00:51 +02:00
.cocciconfig	scripts: add Linux .cocciconfig for coccinelle	2016-07-22 12:13:39 +02:00
.get_maintainer.ignore	Opt out of scripts/get_maintainer.pl	2019-05-16 10:53:40 -07:00
.gitattributes	.gitattributes: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	modpost: dump missing namespaces into a single modules.nsdeps file	2019-11-11 20:10:01 +09:00
.mailmap	MAINTAINERS: update my email address	2020-01-11 14:33:39 -08:00
COPYING	COPYING: use the new text with points to the license files	2018-03-23 12:41:45 -06:00
CREDITS	Linux 5.4-rc4	2019-10-29 04:43:29 -06:00
Kbuild	kbuild: do not descend to ./Kbuild when cleaning	2019-08-21 21:03:58 +09:00
Kconfig	docs: kbuild: convert docs to ReST and rename to *.rst	2019-06-14 14:21:21 -06:00
MAINTAINERS	MAINTAINERS: Update drm/i915 bug filing URL	2020-02-28 17:23:36 +01:00
Makefile	Linux 5.5.7	2020-02-28 17:23:45 +01:00
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.