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

["Sharma, Shashank" <shashank.sharma@intel.com>]

Regards

Shashank


On 1/30/2017 3:47 PM, Andrzej Hajda wrote:
> 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@synopsys.com>
>>>>>> Cc: Alex Deucher <alexander.deucher@amd.com>
>>>>>> Cc: Andrzej Hajda <a.hajda@samsung.com>
>>>>>>
>>>>>> 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@intel.com>
>>>>>> Signed-off-by: Sonika Jindal <sonika.jindal@intel.com>
>>>>>> Reviewed-by: Jose Abreu <Jose.Abreu@synopsys.com>
>>>>>> Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
>>>>>> ---
>>>>> 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.
These claims are not made in HDMI 2.0 specs, CEA is the body which 
defines VICs, AVI-IF and aspects, so its defined in CEA-861-F spec
IF you check the CEA-861-F spec, you will find this section.
>
>> - 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?
As edid_cea_modes is being used in drm_hdmi_avi_if_from_display_mode, 
only place where its being used to load AVI IF (with aspect ratio 
information), I was talking about both.
But lets talk about VIC only from here.

Shashank
>
> Regards
> Andrzej
>

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