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Message-ID: <de559e34-3b56-a3d5-cd7a-89bc8f5528d7@molgen.mpg.de>
Date:   Wed, 30 Mar 2022 08:34:02 +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
To:     Ryan Lin <tsung-hua.lin@amd.com>
Cc:     Chun Ming Zhou <David1.Zhou@amd.com>,
        Drew Davenport <ddavenport@chromium.org>,
        Leo Li <sunpeng.li@amd.com>, leon.li@amd.com,
        dri-devel@lists.freedesktop.org,
        Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>,
        linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org,
        =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>,
        David Airlie <airlied@linux.ie>,
        Sean Paul <seanpaul@chromium.org>,
        Louis Li <ching-shih.li@amd.corp-partner.google.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>,
        Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?Q?St=c3=a9phane_Marchesin?= <marcheu@chromium.org>,
        Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>,
        Harry Wentland <harry.wentland@amd.com>,
        Mark Yacoub <markyacoub@google.com>
References: <20220127081237.13903-1-Tsung-Hua.Lin@amd.com>
 <20220330024643.162230-1-tsung-hua.lin@amd.com>
From:   Paul Menzel <pmenzel@molgen.mpg.de>
In-Reply-To: <20220330024643.162230-1-tsung-hua.lin@amd.com>
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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)