[Intel-gfx] [PATCH 2/2] drm/i915: Crop cursor image for CHV pipe C cursor issue

[Dave Gordon]

On 08/06/16 09:40, Daniel Vetter wrote:
> On Wed, Jun 08, 2016 at 01:57:44PM +0530, Akshu Agrawal wrote:
>> CHV pipe C hits underrun when we get -ve X values of cursor. To avoid
>> this we crop the cursor image for by -ve X value and thus use '0' as
>> least X value.
>
> You're talking about "-ve" here and there's absolutely no "-ve" anywhere
> in your patch. That makes your commit message non-understandable.

That's shorthand for "negative", and some of the code below is indeed 
testing for a negative X coordinate, e.g:

[snip]

>> +	/*
>> +	 * There is an issue in CHV PIPE C where we hit underrun on
>> +	 * -ve value of cursor. To avoid this we are cropping the
>> +	 *  image for all PIPE C -ve values.
>> +	 */
>> +	if (IS_CHERRYVIEW(plane->dev)) {
>> +		if (pipe == PIPE_C && state->visible &&
>> +		    state->base.crtc_x < 0) {
>> +			ret = vlv_cursor_crop(state, crtc_prev_x);
>> +			if (ret)
>> +				return -ENOMEM;
>> +		} else if (crtc_prev_x < 0) { /* Restore the image back */
>> +			char __iomem *base;
>> +			char __iomem *org_image = state->vlv_cursor_image;
>> +			int size = obj->base.size;
>> +
>> +			if (org_image == NULL)
>> +				return -ENOMEM;
>> +			base = vlv_pin_and_map_buffer_obj(obj);
>> +			if (base == NULL)
>> +				return -ENOMEM;
>> +			memcpy(base, org_image, size);
>> +			vlv_unpin_buffer_obj(obj, base);
>> +		}
>> +	}

HTH,
.Dave.