[RFC v2 5/5] drm/i915: Use generic HDMI infoframe helpers

[Daniel Vetter]

On Thu, Dec 6, 2012 at 3:23 PM, Thierry Reding
<thierry.reding at avionic-design.de> wrote:
>> > -   /* sdvo spec says that the ecc is handled by the hw, and it looks like
>> > -    * we must not send the ecc field, either. */
>> > -   memcpy(sdvo_data, &avi_if, 3);
>> > -   sdvo_data[3] = avi_if.checksum;
>>
>> This difference between how we need to send the infoframe to the hw
>> between sdvo (without ecc field present) and native hdmi (ecc field
>> present, but still computed by the hw) seems to have been lost. On a quick
>> read from your infoframe packer it looks like the ecc field isn't part of
>> the packed infoframe, so this patch would break native hdmi ports (in the
>> intel_hdmi.c file).
>
> Actually this ECC field seems to be something specific to Intel
> hardware. It doesn't appear in the HDMI specification nor in CEA-861-D.
> So it the binary infoframe representation doesn't contain it, therefore
> it should be handled by the respective drivers. So in fact the code
> should be working fine for HDMI and SDVO, since for the HDMI ports I
> explicitly left the fourth byte of the header empty, while for SDVO, the
> checksum is the one as computed by hdmi_avi_infoframe_pack(), which is
> at byte 3 and therefore matches the previous code.

Oh dear, I've failed to read the patch correctly and totally missed
the new intel_dip_pack function and assorted logic changes. Sorry for
the confusion.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch