On Fri, Feb 24, 2017 at 5:45 PM, liuxinliang
<z.liuxinliang@xxxxxxxxxxxxx> wrote:
>
>
> On 2017/2/25 9:39, liuxinliang wrote:
>>
>> Hi John,
>>
>> The patch seems good to me, except one minus comment.
>> Maybe change fb_lock to fbdev_lock would be better.
>>
>> Thanks,
>> -xinliang
>>
>> On 2017/2/25 9:25, John Stultz wrote:
>>>
>>> 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
>>> 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.
>>>
>>> Suggestions or feedback would be greatly appreciated!
>>>
>>> Cc: Xinliang Liu <z.liuxinliang@xxxxxxxxxxxxx>
>>> Cc: Rongrong Zou <zourongrong@xxxxxxxxx>
>>> Cc: Xinwei Kong <kong.kongxinwei@xxxxxxxxxxxxx>
>>> Cc: Chen Feng <puck.chen@xxxxxxxxxxxxx>
>>> Cc: David Airlie <airlied@xxxxxxxx>
>>> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
>>> Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
>>> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
>>> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
>>> ---
>>> drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 4 ++++
>>> drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h | 1 +
>>> 2 files changed, 5 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
>>> b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
>>> index 7ec93ae..b83556a 100644
>>> --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
>>> +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
>>> @@ -55,6 +55,7 @@ static void kirin_fbdev_output_poll_changed(struct
>>> drm_device *dev)
>>> {
>>> struct kirin_drm_private *priv = dev->dev_private;
>>> + mutex_lock(&priv->fb_lock);
>>> if (priv->fbdev) {
>>> drm_fbdev_cma_hotplug_event(priv->fbdev);
>>> } else {
>>> @@ -63,6 +64,7 @@ static void kirin_fbdev_output_poll_changed(struct
>>> drm_device *dev)
>>> if (IS_ERR(priv->fbdev))
>>> priv->fbdev = NULL;
>>> }
>>> + mutex_unlock(&priv->fb_lock);
>>> }
>>> #endif
>>> @@ -95,6 +97,8 @@ static int kirin_drm_kms_init(struct drm_device *dev)
>>> if (!priv)
>>> return -ENOMEM;
>>> + mutex_init(&priv->fb_lock);
>
> And put this line in CONFIG_DRM_FBDEV_EMULATION
Ok. Done! Thanks again for the review and feedback!
-john
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
