Re: [PATCH v3] drm/edid: Complete CEA modedb(VIC 1-107)

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On 30.01.2017 10:42, Sharma, Shashank wrote:
> Regards
>
> Shashank
>
>
> On 1/30/2017 2:52 PM, Andrzej Hajda wrote:
>> On 30.01.2017 09:45, Sharma, Shashank wrote:
>>> Regards
>>>
>>> Shashank
>>>
>>>
>>> On 1/30/2017 1:30 PM, Andrzej Hajda wrote:
>>>> On 29.01.2017 06:41, Shashank Sharma wrote:
>>>>> CEA-861-F specs defines new 4k video modes to be used with
>>>>> HDMI 2.0 EDIDs. These modes start at VIC=93 and go all the
>>>>> way till VIC=107.
>>>>>
>>>>> Our existing CEA modedb contains only 64 modes (VIC=1 to VIC=64). Now
>>>>> to be able to parse 4k modes using the existing techniques, we have
>>>>> to complete the modedb (VIC=65 onwards).
>>>>>
>>>>> This patch adds:
>>>>> - Timings for existing CEA video modes (from VIC=65 till VIC=92)
>>>>> - Newly added 4k modes (from VIC=93 to VIC=107).
>>>>>
>>>>> Cc: Jose Abreu <Jose.Abreu@xxxxxxxxxxxx>
>>>>> Cc: Alex Deucher <alexander.deucher@xxxxxxx>
>>>>> Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
>>>>>
>>>>> V2: Addressed review comments from Jose:
>>>>> - fix the timings for VIC 83, 90 and 91
>>>>> - fix formatting for VIC 93-107
>>>>>
>>>>> V3: Rebase on drm-tip
>>>>>
>>>>> Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxxxx>
>>>>> Signed-off-by: Sonika Jindal <sonika.jindal@xxxxxxxxx>
>>>>> Reviewed-by: Jose Abreu <Jose.Abreu@xxxxxxxxxxxx>
>>>>> Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
>>>>> ---
>>>> Have you addressed in some other patch my concerns regarding polluting
>>>> infoframes generated for HDMI 1.4 devices (CEA-861-E) with VICs specific
>>>> only for HDMI 2.0 (CEA-861-F) ? It will happen
>>>> for all UHD modes, see [1][2] for previous discussion.
>>> Hello Andrzej
>>>
>>> As you already know, the aspect ratio is indexed with the VIC, which
>>> comes from EDID.
>>> Now, why would a HDMI 1.4 monitor, contain a HDMI 2.0 VIC ? If it does,
>>> its not compliant.
>> Have you forgot our previous discussion? Let me cite myself:
>>
>> For example 3840x2160@30Hz has no VIC in HDMI 1.4 but it can
>> be present in HDMI vendor specific block with HDMI_VIC 1, on the
>> other side it has VIC 95 in HDMI 2.0. So before your patch
>> AVI infoframe.video_code is set to 0, after your patch is set to 95.
>>
>>
>> And your discussion with Ville:
>>
>>>> />>> No. The user is free to specify any mode they wish. It doesn't
>>> have to/
>>>> />>> come from the EDID. Not sure specifying a modern VIC for an older/
>>>> />>> display is a good idea or not. If not, we could always check the
>>> cea_rev/
>>>> />>> assuming it changed whenever the list if VICs was expanded./
>>>> />> I agree, that user can specify a mode, out of EDID too./
>>>> />> I am anyways planning to add a patch, where before loading HDMI 2.0
>>> VICs/
>>>> />> in AVI IF, we are checking the EDID rev./
>>>> />> That should solve our problem./
>>>> />>/
>>>> />> So if edid_rev < 2.0/
>>>> />> do_not_load VICs from 93 - 107, but keep it 0./
>>>> /> Why edid_rev and not cea_rev?/
>>>> /We can do that also, but in the current structure, we are already /
>>>> /caching EDID rev, its just about re-using it./
>>>> /AFAIK, we don't have CEA extension cached anywhere./
>>> Yes we do.
>> It does not seem to be addressed.
>>
>> Regards
>> Andrzej
> Hey, thanks for bringing this out again. I checked the specs again, 
> there are three things here:
> - The spec has a section on this, and it states that in such cases CEA 
> VIC should be supplied to the AVI IF.

This phrase is not precise, but if it means that in case of
3840x2160@30Hz source should set VIC to 95 also for HDMI1.4 compliant
sinks it is in opposition to statement from HDMI1.4 specification:
> When transmitting any extended video format indicated through use of
> the HDMI_VIC field
> in the HDMI Vendor Specific InfoFrame or any other format which is not
> described in the
> above cases, an HDMI Source shall set the AVI InfoFrame VIC field to zero.

I do not think HDMI20 could invalidate claims from HDMI1.4.


> - Also, for HDMI infoframe blocks, we dont refer to cea_edid_modes[] 
> rather we go to edid_4k_modes[]

cea_edid_modes is used in generating AVI infoframe,
edid_4k_modes is used in generating vendor infoframe

> - Again, as there is no aspect ratio parsing layer in DRM right now 
> (after the revert), we are doing the right thing to give aspect as per 
> CEA, which is suggested by spec too.
>

I do not understand this phrase. Are you talking about aspect ratios or
about video format?

Regards
Andrzej

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