[Intel-gfx] [PATCH] drm/i915/fbdev: Stop repeating tile configuration on stagnation

[Tomasz Lis]

Looks good to me.

Reviewed-by: Tomasz Lis <tomasz.lis at intel.com>


W dniu 2017-02-20 o 16:46, Chris Wilson pisze:
> On Mon, Feb 20, 2017 at 04:37:47PM +0100, Tomasz Lis wrote:
>> I tested this variant (reverted the change to "pass" variable before
>> testing), and it fixes the issue with count=0 as well as possible
>> infinite loop issue.
>>
>> But something needs to be done with the "pass" var, one way or the
>> other - commented below.
>>
>>
>> W dniu 2017-02-18 o 16:37, Chris Wilson pisze:
>>> If we cease making progress in finding matching outputs for a tiled
>>> configuration, stop looping over the remaining unconfigured outputs.
>>>
>>> Fixes: b0ee9e7fa5b4 ("drm/fb: add support for tiled monitor configurations. (v2)")
>>> Cc: Tomasz Lis <tomasz.lis at intel.com>
>>> Cc: Dave Airlie <airlied at redhat.com>
>>> Cc: Daniel Vetter <daniel.vetter at intel.com>
>>> Cc: Jani Nikula <jani.nikula at linux.intel.com>
>>> Cc: Sean Paul <seanpaul at chromium.org>
>>> Cc: <stable at vger.kernel.org> # v3.19+
>>> ---
>>>   drivers/gpu/drm/i915/intel_fbdev.c | 7 +++----
>>>   1 file changed, 3 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
>>> index 041322fef607..32d0af6b07a7 100644
>>> --- a/drivers/gpu/drm/i915/intel_fbdev.c
>>> +++ b/drivers/gpu/drm/i915/intel_fbdev.c
>>> @@ -348,7 +348,7 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
>>>   				    bool *enabled, int width, int height)
>>>   {
>>>   	struct drm_i915_private *dev_priv = to_i915(fb_helper->dev);
>>> -	unsigned long conn_configured, mask;
>>> +	unsigned long conn_configured, conn_seq, mask;
>>>   	unsigned int count = min(fb_helper->connector_count, BITS_PER_LONG);
>>>   	int i, j;
>>>   	bool *save_enabled;
>>> @@ -365,6 +365,7 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
>>>   	mask = GENMASK(count - 1, 0);
>>>   	conn_configured = 0;
>>>   retry:
>>> +	conn_seq = conn_configured;
>>>   	for (i = 0; i < count; i++) {
>>>   		struct drm_fb_helper_connector *fb_conn;
>>>   		struct drm_connector *connector;
>>> @@ -489,10 +490,8 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
>>>   		conn_configured |= BIT(i);
>>>   	}
>>> -	if ((conn_configured & mask) != mask) {
>>> -		pass++;
>> This doesn't seem right; increasing the amount of passes should
>> stay, or the use of "pass" variable should be completely replaced by
>> conn_seq.
> Good catch.
>
> diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
> index 32d0af6b07a7..f7e9a4e69595 100644
> --- a/drivers/gpu/drm/i915/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> @@ -355,7 +355,6 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
>          bool fallback = true;
>          int num_connectors_enabled = 0;
>          int num_connectors_detected = 0;
> -       int pass = 0;
>   
>          save_enabled = kcalloc(count, sizeof(bool), GFP_KERNEL);
>          if (!save_enabled)
> @@ -379,7 +378,7 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
>                  if (conn_configured & BIT(i))
>                          continue;
>   
> -               if (pass == 0 && !connector->has_tile)
> +               if (conn_seq == 0 && !connector->has_tile)
>                          continue;
>   
>                  if (connector->status == connector_status_connected)
>
> Suggestions for a better name than conn_seq much appreciated.
> -Chris
>