Re: [Intel-gfx] [PATCH 3/3] drm/i915/fbdev: Flush mode configuration before lastclose

[Daniel Vetter]

On Fri, Jun 17, 2016 at 06:54:49PM +0100, Chris Wilson wrote:
> During lastclose, we call intel_fbdev_restore_mode() to switch back to
> the fbcon configuration on return to VT. However, if we have not yet
> finished the asynchronous fbdev initialisation, the current mode will be
> invalid and trigger WARNs upon application.
> 
> Serialise with the outstanding initialisation if the first application
> exits quickly. Note that to hit this in practice requires using an
> unregistered async_domain as otherwise modprobe will force a full
> synchronisation prior to init() completing.
> 
> Signed-off-by: Chris Wilson 
> ---
>  drivers/gpu/drm/i915/intel_fbdev.c | 5 +
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_fbdev.c 
> b/drivers/gpu/drm/i915/intel_fbdev.c
> index 638e420a59cb..a19d621d8815 100644
> --- a/drivers/gpu/drm/i915/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> @@ -830,6 +830,11 @@ void intel_fbdev_restore_mode(struct drm_device *dev)
>   if (!ifbdev)
>   return;
>  
> + if (ifbdev->cookie) {
> + async_synchronize_cookie(ifbdev->cookie + 1);
> + ifbdev->cookie = 0;
> + }

I kinda wonder whether we shouldn't move all the fbdev async stuff into
the drm helpers. Same request here about adding a small comment about the
+1, with that:

Reviewed-by: Daniel Vetter 

> +
>   fb_helper = >helper;
>  
>   ret = drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper);
> -- 
> 2.8.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [Intel-gfx] [PATCH 3/3] drm/i915/fbdev: Flush mode configuration before lastclose

[Lukas Wunner]

On Fri, Jun 17, 2016 at 06:54:49PM +0100, Chris Wilson wrote:
> During lastclose, we call intel_fbdev_restore_mode() to switch back to
> the fbcon configuration on return to VT. However, if we have not yet
> finished the asynchronous fbdev initialisation, the current mode will be
> invalid and trigger WARNs upon application.
> 
> Serialise with the outstanding initialisation if the first application
> exits quickly. Note that to hit this in practice requires using an
> unregistered async_domain as otherwise modprobe will force a full
> synchronisation prior to init() completing.
> 
> Signed-off-by: Chris Wilson 

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93580
Reported-by: Gustav Fägerlind 
Reported-by: "Li, Weinan Z" 
Cc: sta...@vger.kernel.org

> ---
>  drivers/gpu/drm/i915/intel_fbdev.c | 5 +
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_fbdev.c 
> b/drivers/gpu/drm/i915/intel_fbdev.c
> index 638e420a59cb..a19d621d8815 100644
> --- a/drivers/gpu/drm/i915/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> @@ -830,6 +830,11 @@ void intel_fbdev_restore_mode(struct drm_device *dev)
>   if (!ifbdev)
>   return;
>  
> + if (ifbdev->cookie) {
> + async_synchronize_cookie(ifbdev->cookie + 1);
> + ifbdev->cookie = 0;
> + }
> +
>   fb_helper = >helper;
>  
>   ret = drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper);
> -- 
> 2.8.1
> 
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[Intel-gfx] [PATCH 3/3] drm/i915/fbdev: Flush mode configuration before lastclose

[Chris Wilson]

During lastclose, we call intel_fbdev_restore_mode() to switch back to
the fbcon configuration on return to VT. However, if we have not yet
finished the asynchronous fbdev initialisation, the current mode will be
invalid and trigger WARNs upon application.

Serialise with the outstanding initialisation if the first application
exits quickly. Note that to hit this in practice requires using an
unregistered async_domain as otherwise modprobe will force a full
synchronisation prior to init() completing.

Signed-off-by: Chris Wilson 
---
 drivers/gpu/drm/i915/intel_fbdev.c | 5 +
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_fbdev.c 
b/drivers/gpu/drm/i915/intel_fbdev.c
index 638e420a59cb..a19d621d8815 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -830,6 +830,11 @@ void intel_fbdev_restore_mode(struct drm_device *dev)
if (!ifbdev)
return;
 
+   if (ifbdev->cookie) {
+   async_synchronize_cookie(ifbdev->cookie + 1);
+   ifbdev->cookie = 0;
+   }
+
fb_helper = >helper;
 
ret = drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper);
-- 
2.8.1

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