[PATCH AUTOSEL 4.19 03/27] drm/tegra: hub: Do not enable orphaned window group

[PATCH AUTOSEL 4.19 03/27] drm/tegra: hub: Do not enable orphaned window group

[Sasha Levin]

From: Nicolin Chen <nicoleotsuka-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

[ Upstream commit ef4e417eb3ec7fe657928f10ac1d2154d8a5fb38 ]

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 <nicoleotsuka-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Sasha Levin <sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 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 bb97cad1eb699..b08ce1125996d 100644
--- a/drivers/gpu/drm/tegra/hub.c
+++ b/drivers/gpu/drm/tegra/hub.c
@@ -143,7 +143,9 @@ 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;
@@ -160,7 +162,9 @@ 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);
 	}
 }
 
-- 
2.25.1

[PATCH AUTOSEL 4.19 04/27] gpu: host1x: Detach driver on unregister

[Sasha Levin]

From: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

[ Upstream commit d9a0a05bf8c76e6dc79230669a8b5d685b168c30 ]

Currently when a host1x device driver is unregistered, it is not
detached from the host1x controller, which means that the device
will stay around and when the driver is registered again, it may
bind to the old, stale device rather than the new one that was
created from scratch upon driver registration. This in turn can
cause various weird crashes within the driver core because it is
confronted with a device that was already deleted.

Fix this by detaching the driver from the host1x controller when
it is unregistered. This ensures that the deleted device also is
no longer present in the device list that drivers will bind to.

Reported-by: Sowjanya Komatineni <skomatineni-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Tested-by: Sowjanya Komatineni <skomatineni-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Sasha Levin <sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 drivers/gpu/host1x/bus.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c
index 0121fe7a4548d..02f896b50ed07 100644
--- a/drivers/gpu/host1x/bus.c
+++ b/drivers/gpu/host1x/bus.c
@@ -632,8 +632,17 @@ EXPORT_SYMBOL(host1x_driver_register_full);
  */
 void host1x_driver_unregister(struct host1x_driver *driver)
 {
+	struct host1x *host1x;
+
 	driver_unregister(&driver->driver);
 
+	mutex_lock(&devices_lock);
+
+	list_for_each_entry(host1x, &devices, list)
+		host1x_detach_driver(host1x, driver);
+
+	mutex_unlock(&devices_lock);
+
 	mutex_lock(&drivers_lock);
 	list_del_init(&driver->list);
 	mutex_unlock(&drivers_lock);
-- 
2.25.1