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Message-ID: <7c7ec347-4372-31ac-94ed-5d20602c6ce2@molgen.mpg.de>
Date:   Wed, 30 Mar 2022 08:36:22 +0200
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Subject: Re: [PATCH v2] drm/amdgpu: fix that issue that the number of the crtc
 of the 3250c is not correct
Content-Language: en-US
From:   Paul Menzel <pmenzel@molgen.mpg.de>
To:     Ryan Lin <tsung-hua.lin@amd.com>
Cc:     =?UTF-8?Q?St=c3=a9phane_Marchesin?= <marcheu@chromium.org>,
        Leo Li <sunpeng.li@amd.com>, leon.li@amd.com,
        Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>,
        David Airlie <airlied@linux.ie>,
        Sean Paul <seanpaul@chromium.org>,
        amd-gfx@lists.freedesktop.org, Daniel Vetter <daniel@ffwll.ch>,
        Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>,
        Drew Davenport <ddavenport@chromium.org>,
        Alex Deucher <alexander.deucher@amd.com>,
        Mark Yacoub <markyacoub@google.com>,
        Harry Wentland <harry.wentland@amd.com>,
        =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>,
        Louis Li <ching-shih.li@amd.corp-partner.google.com>
References: <20220127081237.13903-1-Tsung-Hua.Lin@amd.com>
 <20220330024643.162230-1-tsung-hua.lin@amd.com>
 <de559e34-3b56-a3d5-cd7a-89bc8f5528d7@molgen.mpg.de>
In-Reply-To: <de559e34-3b56-a3d5-cd7a-89bc8f5528d7@molgen.mpg.de>
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[Cc: Remove undeliverable Chun Ming Zhou <mailto:David1.Zhou@amd.com>]

Am 30.03.22 um 08:34 schrieb Paul Menzel:
> Dear Tsung-Hua,
> 
> 
> Thank you for your patch.
> 
> Am 30.03.22 um 04:46 schrieb Ryan Lin:
> 
> The commit message summary is quite long and confusing. Maybe:
> 
> Use 3 CRTC for 3250c to get internal display working
> 
>> [Why]
>> External displays take priority over internal display when there are 
>> fewer
>> display controllers than displays.
> 
> This causes the internal display to not work on the Chromebook google/zork.
> 
>> [How]
>> The root cause is because of that number of the crtc is not correct.
> 
> The root cause is the incorrect number of four configured CRTCs.
> 
>> The number of the crtc on the 3250c is 3, but on the 3500c is 4.
>> On the source code, we can see that number of the crtc has been fixed 
>> at 4.
>> Needs to set the num_crtc to 3 for 3250c platform.
> 
> Please do not wrap lines after each sentence, and use a text width of 75 
> characters.
> 
>> v2:
>>     - remove unnecessary comments and Id
>>
>> Signed-off-by: Ryan Lin <tsung-hua.lin@amd.com>
>>
>> ---
>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 +++++++++---
>>   1 file changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c 
>> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> index 40c91b448f7da..455a2c45e8cda 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> @@ -2738,9 +2738,15 @@ static int dm_early_init(void *handle)
>>           break;
>>   #if defined(CONFIG_DRM_AMD_DC_DCN1_0)
>>       case CHIP_RAVEN:
>> -        adev->mode_info.num_crtc = 4;
>> -        adev->mode_info.num_hpd = 4;
>> -        adev->mode_info.num_dig = 4;
>> +        if (adev->rev_id >= 8) {
> 
> Is there some define for that number? Maybe add a comment, that it’s for 
> 3250c?
> 
> 
> Kind regards,
> 
> Paul
> 
> 
>> +            adev->mode_info.num_crtc = 3;
>> +            adev->mode_info.num_hpd = 3;
>> +            adev->mode_info.num_dig = 3;
>> +        } else {
>> +            adev->mode_info.num_crtc = 4;
>> +            adev->mode_info.num_hpd = 4;
>> +            adev->mode_info.num_dig = 4;
>> +        }
>>           break;
>>   #endif
>>   #if defined(CONFIG_DRM_AMD_DC_DCN2_0)