From: Thomas Zimmermann Date: Mon, 16 May 2022 13:43:37 +0000 (+0200) Subject: drm/mgag200: Acquire I/O lock while reading EDID X-Git-Tag: baikal/mips/sdk6.1~5152^2~22^2~89 X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=ea09093305b25faf484a4e1a90c3b227997cdbc3;p=kernel.git drm/mgag200: Acquire I/O lock while reading EDID 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 946965594140 ("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 Fixes: 946965594140 ("drm/mgag200: Protect concurrent access to I/O registers with lock") Reviewed-by: Jocelyn Falempe Tested-by: Jocelyn Falempe Cc: Thomas Zimmermann Cc: Jocelyn Falempe Cc: Daniel Vetter Cc: Dave Airlie Cc: dri-devel@lists.freedesktop.org Link: https://patchwork.freedesktop.org/patch/msgid/20220516134343.6085-2-tzimmermann@suse.de --- diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c index 73d5a4a42b3a0..762b9657ae8d3 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; }