From a9748134ea4aad989e52a6a91479e0acfd306e5b Mon Sep 17 00:00:00 2001 From: Fabio Estevam Date: Sat, 20 Mar 2021 08:56:03 -0300 Subject: drm/msm: Fix suspend/resume on i.MX5 When putting iMX5 into suspend, the following flow is observed: [ 70.023427] [] (msm_atomic_commit_tail) from [] (commit_tail+0x9c/0x18c) [ 70.031890] [] (commit_tail) from [] (drm_atomic_helper_commit+0x1a0/0x1d4) [ 70.040627] [] (drm_atomic_helper_commit) from [] (drm_atomic_helper_disable_all+0x1c4/0x1d4) [ 70.050913] [] (drm_atomic_helper_disable_all) from [] (drm_atomic_helper_suspend+0xb8/0x170) [ 70.061198] [] (drm_atomic_helper_suspend) from [] (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 Signed-off-by: Rob Clark --- 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 fd2ac54caf9f..a5c6b8c23336 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -1072,6 +1072,10 @@ 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); } @@ -1079,6 +1083,10 @@ 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); } -- cgit v1.2.3