DDC operation conflicts with concurrent mode setting. Acquire the
driver's I/O lock in get_modes to prevent this. This change should
have been part of commit 931e3f3a0e99 ("drm/mgag200: Protect
concurrent access to I/O registers with lock"), but apparently got
lost somewhere.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Fixes: 931e3f3a0e99 ("drm/mgag200: Protect concurrent access to I/O registers with lock")
Reviewed-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
Tested-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
---
drivers/gpu/drm/mgag200/mgag200_mode.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
index 73d5a4a42b3a..762b9657ae8d 100644
--- a/drivers/gpu/drm/mgag200/mgag200_mode.c
+++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
@@ -691,16 +691,26 @@ static void mgag200_disable_display(struct mga_device *mdev)
static int mga_vga_get_modes(struct drm_connector *connector)
{
+ struct mga_device *mdev = to_mga_device(connector->dev);
struct mga_connector *mga_connector = to_mga_connector(connector);
struct edid *edid;
int ret = 0;
+ /*
+ * Protect access to I/O registers from concurrent modesetting
+ * by acquiring the I/O-register lock.
+ */
+ mutex_lock(&mdev->rmmio_lock);
+
edid = drm_get_edid(connector, &mga_connector->i2c->adapter);
if (edid) {
drm_connector_update_edid_property(connector, edid);
ret = drm_add_edid_modes(connector, edid);
kfree(edid);
}
+
+ mutex_unlock(&mdev->rmmio_lock);
+
return ret;
}
--
2.36.1
