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Hi Chandan,

This issue we found on the Zork project which uses the kernel 5.4 on. So I just 
implemented it on kernel 5.4.
For finding out which is 3250c, I referenced the function which is implemented 
from another function.
Below is the part where I found it.

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c-
        case CHIP_RAVEN:
                if (adev->rev_id >= 8)
                        chip_name = "raven2";
                else if (adev->pdev->device == 0x15d8)
                        chip_name = "picasso";
                else
                        chip_name = "raven";
                break;

BR,
Ryan Lin.

-----Original Message-----
From: VURDIGERENATARAJ, CHANDAN <[email protected]> 
Sent: Wednesday, March 30, 2022 12:30 PM
To: Lin, Tsung-hua (Ryan) <[email protected]>
Cc: David (ChunMing) Zhou <[email protected]>; Drew Davenport 
<[email protected]>; Li, Sun peng (Leo) <[email protected]>; Li, Leon 
<[email protected]>; [email protected]; Siqueira, Rodrigo 
<[email protected]>; [email protected]; 
[email protected]; Koenig, Christian <[email protected]>; 
David Airlie <[email protected]>; Sean Paul <[email protected]>; Louis Li 
<[email protected]>; Daniel Vetter <[email protected]>; 
Bas Nieuwenhuizen <[email protected]>; Deucher, Alexander 
<[email protected]>; Stéphane Marchesin <[email protected]>; 
Kazlauskas, Nicholas <[email protected]>; Wentland, Harry 
<[email protected]>; Lin, Tsung-hua (Ryan) <[email protected]>; Mark 
Yacoub <[email protected]>
Subject: RE: [PATCH v2] drm/amdgpu: fix that issue that the number of the crtc 
of the 3250c is not correct


Hi Ryan,

Is this change applicable on a specific kernel version?
On latest I see IP DISCOVERY based impl for CHIP_RAVEN.

>[Why]
>External displays take priority over internal display when there are fewer 
>display controllers than displays.
>
> [How]
>The root cause is because of that number of the crtc is not correct.
>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.
>
>v2:
>   - remove unnecessary comments and Id
>
>Signed-off-by: Ryan Lin <[email protected]>
>
>---
> 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) {

May I know what this ">=8" indicate? Also, should it be external_rev_id if its 
based on old version?

>+                      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)
>--
>2.25.1
>

BR,
Chandan V N

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