In some cases I've been seeing a race where two framebuffers would be initialized, as kirin_fbdev_output_poll_changed() might get called quickly in succession, resulting in the fb initialization happening twice. This could cause the system to boot up with a blank screen.
This patch adds a simple mutex to serialize it and seems to avoid the race. Obviously I suspect this patch isn't the best solution, but I wanted to send it out as something concrete to discuss the bug. Suggestions or feedback for a better solution would be greatly appreciated. Cc: Xinliang Liu <[email protected]> Cc: Rongrong Zou <[email protected]> Cc: Xinwei Kong <[email protected]> Cc: Chen Feng <[email protected]> Cc: David Airlie <[email protected]> Cc: Daniel Vetter <[email protected]> Cc: Sean Paul <[email protected]> Cc: [email protected] Signed-off-by: John Stultz <[email protected]> --- drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c index ebd5f4f..80c607f 100644 --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c @@ -50,11 +50,13 @@ static int kirin_drm_kms_cleanup(struct drm_device *dev) return 0; } +static DEFINE_MUTEX(fb_lock); #ifdef CONFIG_DRM_FBDEV_EMULATION static void kirin_fbdev_output_poll_changed(struct drm_device *dev) { struct kirin_drm_private *priv = dev->dev_private; + mutex_lock(&fb_lock); if (priv->fbdev) { drm_fbdev_cma_hotplug_event(priv->fbdev); } else { @@ -64,6 +66,7 @@ static void kirin_fbdev_output_poll_changed(struct drm_device *dev) if (IS_ERR(priv->fbdev)) priv->fbdev = NULL; } + mutex_unlock(&fb_lock); } #endif -- 2.7.4 _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
