From: Fabio Estevam festevam@gmail.com
[ Upstream commit a9748134ea4aad989e52a6a91479e0acfd306e5b ]
When putting iMX5 into suspend, the following flow is observed:
[ 70.023427] [<c07755f0>] (msm_atomic_commit_tail) from [<c06e7218>] (commit_tail+0x9c/0x18c) [ 70.031890] [<c06e7218>] (commit_tail) from [<c0e2920c>] (drm_atomic_helper_commit+0x1a0/0x1d4) [ 70.040627] [<c0e2920c>] (drm_atomic_helper_commit) from [<c06e74d4>] (drm_atomic_helper_disable_all+0x1c4/0x1d4) [ 70.050913] [<c06e74d4>] (drm_atomic_helper_disable_all) from [<c0e2943c>] (drm_atomic_helper_suspend+0xb8/0x170) [ 70.061198] [<c0e2943c>] (drm_atomic_helper_suspend) from [<c06e84bc>] (drm_mode_config_helper_suspend+0x24/0x58)
In the i.MX5 case, priv->kms is not populated (as i.MX5 does not use any of the Qualcomm display controllers), causing a NULL pointer dereference in msm_atomic_commit_tail():
[ 24.268964] 8<--- cut here --- [ 24.274602] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 24.283434] pgd = (ptrval) [ 24.286387] [00000000] *pgd=ca212831 [ 24.290788] Internal error: Oops: 17 [#1] SMP ARM [ 24.295609] Modules linked in: [ 24.298777] CPU: 0 PID: 197 Comm: init Not tainted 5.11.0-rc2-next-20210111 #333 [ 24.306276] Hardware name: Freescale i.MX53 (Device Tree Support) [ 24.312442] PC is at msm_atomic_commit_tail+0x54/0xb9c [ 24.317743] LR is at commit_tail+0xa4/0x1b0
Fix the problem by calling drm_mode_config_helper_suspend/resume() only when priv->kms is available.
Fixes: ca8199f13498 ("drm/msm/dpu: ensure device suspend happens during PM sleep") Signed-off-by: Fabio Estevam festevam@gmail.com Signed-off-by: Rob Clark robdclark@chromium.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/msm/msm_drv.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c index 45e325c982c2..b38ebccad42f 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -1079,6 +1079,10 @@ static int __maybe_unused msm_pm_resume(struct device *dev) static int __maybe_unused msm_pm_prepare(struct device *dev) { struct drm_device *ddev = dev_get_drvdata(dev); + struct msm_drm_private *priv = ddev ? ddev->dev_private : NULL; + + if (!priv || !priv->kms) + return 0;
return drm_mode_config_helper_suspend(ddev); } @@ -1086,6 +1090,10 @@ static int __maybe_unused msm_pm_prepare(struct device *dev) static void __maybe_unused msm_pm_complete(struct device *dev) { struct drm_device *ddev = dev_get_drvdata(dev); + struct msm_drm_private *priv = ddev ? ddev->dev_private : NULL; + + if (!priv || !priv->kms) + return;
drm_mode_config_helper_resume(ddev); }