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Brian Norris c41963e50a drm/rockchip: vop: Leave vblank enabled in self-refresh
commit 2bdba9d4a3baa758c2ca7f5b37b35c7b3391dc42 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>
2023-07-23 13:49:39 +02:00
arch MIPS: KVM: Fix NULL pointer dereference 2023-07-23 13:49:33 +02:00
block blk-crypto: use dynamic lock class for blk_crypto_profile::lock 2023-07-23 13:49:21 +02:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: jitter - correct health test during initialization 2023-07-19 16:21:42 +02:00
Documentation dm init: add dm-mod.waitfor to wait for asynchronously probed block devices 2023-07-23 13:49:38 +02:00
drivers drm/rockchip: vop: Leave vblank enabled in self-refresh 2023-07-23 13:49:39 +02:00
fs fs: dlm: fix mismatch of plock results from userspace 2023-07-23 13:49:38 +02:00
include net/sched: make psched_mtu() RTNL-less safe 2023-07-23 13:49:27 +02:00
init gcc: disable '-Warray-bounds' for gcc-13 too 2023-04-26 14:28:43 +02:00
io_uring io_uring: Use io_schedule* in cqring wait 2023-07-19 16:22:18 +02:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel tracing/user_events: Fix incorrect return value for writing operation when events are disabled 2023-07-23 13:49:32 +02:00
lib lib/bitmap: drop optimization of bitmap_{from,to}_arr64 2023-07-19 16:21:58 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm kasan: add kasan_tag_mismatch prototype 2023-07-23 13:49:32 +02:00
net net/sched: sch_qfq: account for stab overhead in qfq_enqueue 2023-07-23 13:49:27 +02:00
rust rust: kernel: Mark rust_fmt_argument as extern "C" 2023-04-26 14:28:38 +02:00
samples samples/bpf: xdp1 and xdp2 reduce XDPBUFSIZE to 60 2023-07-19 16:21:07 +02:00
scripts kbuild: Disable GCOV for *.mod.o 2023-07-19 16:21:44 +02:00
security integrity: Fix possible multiple allocation in integrity_inode_get() 2023-07-19 16:22:11 +02:00
sound ASoC: mediatek: mt8173: Fix snd_soc_component_initialize error path 2023-07-19 16:22:14 +02:00
tools wireguard: netlink: send staged packets when setting initial private key 2023-07-19 16:22:17 +02:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Avoid illegal stage2 mapping on invalid memory slot 2023-06-28 11:12:23 +02:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
.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: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
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 smb: move client and server files to common directory fs/smb 2023-06-28 11:12:40 +02:00
Makefile Linux 6.1.39 2023-07-19 16:22:18 +02:00
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.