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.
v3: * fix commit message to say 'drm/mgag200' (Jocelyn)
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Fixes: 931e3f3a0e99 ("drm/mgag200: Protect concurrent access to I/O registers with lock") Reviewed-by: Jocelyn Falempe jfalempe@redhat.com Tested-by: Jocelyn Falempe jfalempe@redhat.com Cc: Thomas Zimmermann tzimmermann@suse.de Cc: Jocelyn Falempe jfalempe@redhat.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Dave Airlie airlied@redhat.com Cc: dri-devel@lists.freedesktop.org --- 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; }