From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolin Chen Subject: [PATCH] drm/tegra: hub: Do not enable orphaned window group Date: Tue, 19 May 2020 02:03:01 -0700 Message-ID: <20200519090301.32689-1-nicoleotsuka@gmail.com> Return-path: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Cc: airlied-cv59FeDIM0c@public.gmane.org, daniel-/w4YWyX8dFk@public.gmane.org, jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org Though the unconditional enable/disable code is not a final solution, we don't want to run into a NULL pointer situation when window group doesn't link to its DC parent if the DC is disabled in Device Tree. So this patch simply adds a check to make sure that window group has a valid parent before running into tegra_windowgroup_enable/disable. Signed-off-by: Nicolin Chen --- drivers/gpu/drm/tegra/hub.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/tegra/hub.c b/drivers/gpu/drm/tegra/hub.c index 8183e617bf6b..a2ef8f218d4e 100644 --- a/drivers/gpu/drm/tegra/hub.c +++ b/drivers/gpu/drm/tegra/hub.c @@ -149,7 +149,9 @@ int tegra_display_hub_prepare(struct tegra_display_hub *hub) for (i = 0; i < hub->soc->num_wgrps; i++) { struct tegra_windowgroup *wgrp = &hub->wgrps[i]; - tegra_windowgroup_enable(wgrp); + /* Skip orphaned window group whose parent DC is disabled */ + if (wgrp->parent) + tegra_windowgroup_enable(wgrp); } return 0; @@ -166,7 +168,9 @@ void tegra_display_hub_cleanup(struct tegra_display_hub *hub) for (i = 0; i < hub->soc->num_wgrps; i++) { struct tegra_windowgroup *wgrp = &hub->wgrps[i]; - tegra_windowgroup_disable(wgrp); + /* Skip orphaned window group whose parent DC is disabled */ + if (wgrp->parent) + tegra_windowgroup_disable(wgrp); } } -- 2.17.1