[Intel-gfx] [PATCH 1/2] Revert "drm/i915: Add eDP intermediate frequencies for CHV"

Sivakumar Thulasimani sivakumar.thulasimani at intel.com
Fri Aug 14 00:31:35 PDT 2015



On 8/14/2015 12:29 PM, Jani Nikula wrote:
> On Wed, 12 Aug 2015, Daniel Vetter <daniel at ffwll.ch> wrote:
>> On Wed, Aug 12, 2015 at 04:02:17PM +0300, Ville Syrjälä wrote:
>>> On Wed, Aug 12, 2015 at 05:31:55PM +0530, Sivakumar Thulasimani wrote:
>>>>
>>>> On 8/12/2015 5:02 PM, Ville Syrjälä wrote:
>>>>> On Fri, Jul 31, 2015 at 11:32:52AM +0530, Sivakumar Thulasimani wrote:
>>>>>> From: "Thulasimani,Sivakumar" <sivakumar.thulasimani at intel.com>
>>>>>>
>>>>>> This reverts
>>>>>> commit fe51bfb95c996733150c44d21e1c9f4b6322a326.
>>>>>> Author: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>>>> Date:   Thu Mar 12 17:10:38 2015 +0200
>>>>>>
>>>>>> CHV does not support intermediate frequencies so reverting the
>>>>>> patch that added it in the first place
>>>>> My docs still say it does. Is there some undocumented problem with the
>>>>> PLL or is this just a marketing decision?
>>>> I don't think so, i too have just one document that shows the phy values
>>>> for each of
>>>> the link rates but have not found any where else to say it is supported .
>>> Display cluster HAS says they're supported. And since the spreadsheet
>>> has them all in green I assume someone actually figured that they ought
>>> to work.
>>>
>>>> Also this is not tested by anyone including us from product team so i
>>>> highly doubt
>>>>    it will even work.
>>> Well if no one has tested them I guess we shouldn't try to use them. Not
>>> a big loss in any case I suppose.
>>>
>>> So based on that reasoning I can give an ack for this patch:
>>> Acked-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>
>>>> regarding HBR2, it was supposed to land on a future stepping that never
>>>> happened
>>>> so it is not supported at all.
>>> Hmm. Display Cluster HAS listed it as a stretch goal for early steppings. Apart
>>> from that there isn't much else to go by. Excepth the training pattern 3
>>> support, but now that I look again the new bit for that has disappeared
>>> from the DP register in the spec. Or maybe I was looking at the k0 spec
>>> when I added it. It's still in the k0 spec but as you say that's been
>>> nuked.
>>>
>>> In light of this, I think dropping HBR2 is reasonable. HBR is anyway
>>> enough for 4k at 30 with 4 lanes, so it's not like we really need HBR2.
>>>
>>> And could you also cook up a patch to kill the training pattern 3
>>> support for CHV? Should be mostly a revert of my original patch that
>>> added it, but you probably need to adjust the use_tps3 condition a bit
>>> too.
>> Can we please grill the people responsible for this docs mess some more?
>>
>> Patch itself is for Jani.
> There was some suggestions from Ville [1] to patch 1/2 that I haven't
> seen a reply to.
>
> BR,
> Jani.
>
> [1] http://mid.gmane.org/20150812131205.GW5176@intel.com
>
>
yes, i can make that change. i was assuming that since Daniel's reply 
had message
"patch itself is for Jani" that you would pick it up :), will check once 
before waiting
next time.
>> -Daniel
>> -- 
>> Daniel Vetter
>> Software Engineer, Intel Corporation
>> http://blog.ffwll.ch

-- 
regards,
Sivakumar



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