Re: [Intel-gfx] [PATCH 2/4] drm/i915: Call non-locking version of drm_kms_helper_poll_enable()

[Daniel Vetter]

On Tue, Sep 01, 2015 at 10:21:33PM +0200, Egbert Eich wrote:
> drm_kms_helper_poll_enable() is called from a context in
> intel_hpd_irq_storm_disable() where the the mode_config mutex is
> already locked.
> When this function was converted to lock this mutex in:
> 
> commit 8c4ccc4ab6f64e859d4ff8d7c02c2ed2e956e07f
> Author: Daniel Vetter 
> Date:   Thu Jul 9 23:44:26 2015 +0200
> 
> drm/probe-helper: Grab mode_config.mutex in poll_init/enable
> 
> a deadlock occurred.
> Call the newly implemented non-locking version of this function.
> 
> Signed-off-by: Egbert Eich 

Oops. Reviewed-by: Daniel Vetter  if you do the
s/_no_lock/_locked/ for consistency on both patch 1&2.
-Daniel

> ---
>  drivers/gpu/drm/i915/intel_hotplug.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_hotplug.c 
> b/drivers/gpu/drm/i915/intel_hotplug.c
> index 53c0173..77dd5b6 100644
> --- a/drivers/gpu/drm/i915/intel_hotplug.c
> +++ b/drivers/gpu/drm/i915/intel_hotplug.c
> @@ -180,7 +180,7 @@ static void intel_hpd_irq_storm_disable(struct 
> drm_i915_private *dev_priv)
>  
>   /* Enable polling and queue hotplug re-enabling. */
>   if (hpd_disabled) {
> - drm_kms_helper_poll_enable(dev);
> + drm_kms_helper_poll_enable_no_lock(dev);
>   mod_delayed_work(system_wq, _priv->hotplug.reenable_work,
>msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
>   }
> -- 
> 1.8.4.5
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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[Intel-gfx] [PATCH 2/4] drm/i915: Call non-locking version of drm_kms_helper_poll_enable()

[Egbert Eich]

drm_kms_helper_poll_enable() is called from a context in
intel_hpd_irq_storm_disable() where the the mode_config mutex is
already locked.
When this function was converted to lock this mutex in:

commit 8c4ccc4ab6f64e859d4ff8d7c02c2ed2e956e07f
Author: Daniel Vetter 
Date:   Thu Jul 9 23:44:26 2015 +0200

drm/probe-helper: Grab mode_config.mutex in poll_init/enable

a deadlock occurred.
Call the newly implemented non-locking version of this function.

Signed-off-by: Egbert Eich 
---
 drivers/gpu/drm/i915/intel_hotplug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_hotplug.c 
b/drivers/gpu/drm/i915/intel_hotplug.c
index 53c0173..77dd5b6 100644
--- a/drivers/gpu/drm/i915/intel_hotplug.c
+++ b/drivers/gpu/drm/i915/intel_hotplug.c
@@ -180,7 +180,7 @@ static void intel_hpd_irq_storm_disable(struct 
drm_i915_private *dev_priv)
 
/* Enable polling and queue hotplug re-enabling. */
if (hpd_disabled) {
-   drm_kms_helper_poll_enable(dev);
+   drm_kms_helper_poll_enable_no_lock(dev);
mod_delayed_work(system_wq, _priv->hotplug.reenable_work,
 msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
}
-- 
1.8.4.5

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