Re: [PATCH 4/4] drm/msm: Fix default fb var width and height

[Rob Clark]

On Fri, Mar 6, 2015 at 1:12 PM, Rob Clark <robdclark@xxxxxxxxx> wrote:
> On Thu, Mar 5, 2015 at 3:20 PM, Hai Li <hali@xxxxxxxxxxxxxx> wrote:
>> The framebuffer var width and height should reflect the size of
>> framebuffer memory allocated, which is the entire surface size.
>>
>> In case of dual DSI connectors with TILE properties, this change
>> makes the whole image show on the dual DSI panel, instead of
>> duplicated images on both sides.
>>
>> Signed-off-by: Hai Li <hali@xxxxxxxxxxxxxx>
>> ---
>>  drivers/gpu/drm/msm/msm_fbdev.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
>> index df60f65..d3e8b14 100644
>> --- a/drivers/gpu/drm/msm/msm_fbdev.c
>> +++ b/drivers/gpu/drm/msm/msm_fbdev.c
>> @@ -169,7 +169,8 @@ static int msm_fbdev_create(struct drm_fb_helper *helper,
>>         }
>>
>>         drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->depth);
>> -       drm_fb_helper_fill_var(fbi, helper, sizes->fb_width, sizes->fb_height);
>> +       drm_fb_helper_fill_var(fbi, helper,
>> +                       sizes->surface_width, sizes->surface_height);
>>
>
> so, I believe the intention for separation if surface_width/height and
> fb_width/height, it to allocate a buffer that is big enough (width and
> height) for all connected displays (so as to not leave some display
> scanning out too small of a buffer), but size the fbdev buffer small
> enough that text would be visible on all screens.  Using
> surface_width/height here instead of fb_width/height would break that.
>
> But I think I have a different idea.. we could implement fb helper
> func initial_config() to just call drm_pick_crtcs() (which we'd have
> to export), and then for each of the crtcs[n] connected to a connector
> with TILE property, populate the offsets[n].x/y.  Or possibly we
> should just make drm_setup_crtcs() clever enough to do that
> automatically.. that would result in larger fb_size and the two crtc's
> scanning out their own parts of the buffer.

Oh, I spoke too soon.. looks like Dave already added it in
drm_get_tile_offsets()..

BR,
-R
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