[B][PATCH v3 0/2] Revert drm/msm patches that cause certification testing failure

[Kelsey Skunberg]

BugLink: https://bugs.launchpad.net/bugs/1877657

[SRU Justification]

[Impact]

snap certification testing failed with bionic/linux-snapdragon

https://bugs.launchpad.net/bugs/1874763

After investigations by Kleber, failure was found to be from a drm driver which
is compiled when CONFIG_DRM_MSM is set.

Information reported from Paul Larson [1]:

We have a cold reboot test in checkbox that seems to be failing with this
kernel. The test runs the following commands to try to trigger a cold reboot:
rtcwake --mode no -s 120 sleep 5 rtcwake -m show sleep 5 dbus-send --system
--print-reply --dest=org.freedesktop.login1 /org/freedesktop/login1
"org.freedesktop.login1.Manager.PowerOff" boolean:true

However, the system never fully reboots. On the serial console, I just see:
...
Press enter to configure.
[ 137.402465] systemd-shutdown[1]: Failed to wait for process: Protocol error
[ 137.406163] systemd-shutdown[1]: Failed to wait for process: Protocol error

I do have the ability to remotely remove power from the device and restore it,
however after doing that, I get an oops on the serial console and the system
never comes up.

[1] https://bugs.launchpad.net/kernel-sru-workflow/+bug/1874763/comments/1

[Test]
Run Certification Testing

The tests are ran only with UC18, so a kernel snap is needed to either build a
new image or promote it to edge.

[Fix]

Revert upstream commits on Bionic/linux:

0519bad6f34f drm/msm: Use the correct dma_sync calls in msm_gem
7318c5ef642b drm/msm: stop abusing dma_map/unmap for cache

[Risk of Regression]

Alternative solutions would need to be found for dma_sync calls in msm_gem and
to avoid abusing dma_map/unmap for cache. The commits both came from upstream
stable.

Changes since v1: Fixed cover letter title that was cut off
Changes since v2: Fixed incorrect revert and reference to upstream commit 

Kelsey Skunberg (2):
  Revert "drm/msm: Use the correct dma_sync calls in msm_gem"
  Revert "drm/msm: stop abusing dma_map/unmap for cache"

 drivers/gpu/drm/msm/msm_gem.c | 47 ++++-------------------------------
 1 file changed, 5 insertions(+), 42 deletions(-)

-- 
2.20.1