Re: [PATCH 1/4] pxa_camera: Remove YUV planar formats hole

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----- Mail Original -----
De: "Guennadi Liakhovetski" <g.liakhovetski@xxxxxx>
À: "Trent Piepho" <xyzzy@xxxxxxxxxxxxx>
Cc: "Robert Jarzmik" <robert.jarzmik@xxxxxxx>, mike@xxxxxxxxxxxxxx, "Linux Media Mailing List" <linux-media@xxxxxxxxxxxxxxx>
Envoyé: Jeudi 5 Mars 2009 23h15:03 GMT +01:00 Amsterdam / Berlin / Berne / Rome / Stockholm / Vienne
Objet: Re: [PATCH 1/4] pxa_camera: Remove YUV planar formats hole

> Yes, adjusting both is also what I was suggesting in my original review. 
> How about aligning the bigger of the two to 4 bytes and the smaller to 2? 

Yes, sounds good.

I remade my calculations :
 - if (width x height % 8 == 0) :
   => frame size = width x height x 2
   => U plane size = frame size / 4 = width x height /2
   => U plane size is a multiple of 4
      As the last DMA load from QIF fifo will return 8 bytes (and not 4 as 
      we would expect, cf. PXA Developer's Manual, 27.4.4.1), this is not
      good.

This implies that even if DMA is 8 bytes aligned, width x height should be a multiple of 16, not 8 as I stated in the first git comment. So that would align :
 - width on 4 bytes (aligning meaning the lowest multiple of 4 below or equal to width)
 - and height on 4 bytes (aligning meaning the lowest multiple of 4 below or equal to height)

Do we have an agreement on that specification, so that I can amend the code accordingly ?

Cheers.

--
Robert
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