Re: [PATCH v4 2/2] drm/i915/display: Disable pipe joiner on WCL

["Borah, Chaitanya Kumar" <chaitanya.kumar.borah@intel.com>]

On 10/28/2026 2:27 PM, Srinivas, Vidya wrote:
> 
> 
>> -----Original Message-----
>> From: Borah, Chaitanya Kumar <chaitanya.kumar.borah@intel.com>
>> Sent: 28 October 2026 14:08
>> To: Srinivas, Vidya <vidya.srinivas@intel.com>; intel-gfx@lists.freedesktop.org
>> Cc: intel-xe@lists.freedesktop.org; stable@vger.kernel.org; Shankar, Uma
>> <uma.shankar@intel.com>; jani.nikula@linux.intel.com; Lin, Charlton
>> <charlton.lin@intel.com>
>> Subject: Re: [PATCH v4 2/2] drm/i915/display: Disable pipe joiner on WCL
>>
>>
>>
>> On 10/28/2026 12:34 PM, Vidya Srinivas wrote:
>>> Pipe joining is not supported in the WCL display configuration.
>>> Report no joiner support on WCL so that modes which would require
>>> joining are rejected, matching the 4k 60Hz maximum resolution
>>> documented for the platform.
>>>
>>> v2: Rebase onto latest upstream
>>> v3: Fix up the commit message
>>> v4: Split the scaler and joiner changes into separate patches (Jani)
>>>
>>> Bspec: 74286
>>> Cc: stable@vger.kernel.org
>>
>> Won't we need a Fixes tag to tell where this change need to go to?
> 
> Hello Chaitanya,
> 
> Thank you. Yes, I did check checkpatch gave the same warning but I couldn’t find the exact patch to call out the fixes
> There are patches like Extend the max dotclock limit to WCL, Restrict max source rate for WCL to HBR3,
> drm/i915/wcl: Add display device info, Add power well mapping for WCL etc.
> git log shows under merge tag the "Add support for Wildcat Lake (WCL) display, version 30.02"
> So, could not find the patch for which I could mention fixes.

Fixes: 632633d095b6 ("drm/i915/wcl: Add display device info")

Should be sufficient.

> 
> Regards
> Vidya
> 
>>
>>> Suggested-by: Charlton Lin <charlton.lin@intel.com>
>>> Reviewed-by: Uma Shankar <uma.shankar@intel.com>
>>> Signed-off-by: Vidya Srinivas <vidya.srinivas@intel.com>
>>> ---
>>>    drivers/gpu/drm/i915/display/intel_dp.c | 4 ++--
>>>    1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
>>> b/drivers/gpu/drm/i915/display/intel_dp.c
>>> index 00e02e019d25..ef164a797618 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>>> @@ -485,9 +485,9 @@ bool intel_dp_has_joiner(struct intel_dp *intel_dp)
>>>    			return false;
>>>    	}
>>>
>>> -	return DISPLAY_VER(display) >= 12 ||
>>> +	return ((DISPLAY_VER(display) >= 12 && DISPLAY_VERx100(display) !=
>>> +3002) ||
>>>    		(DISPLAY_VER(display) == 11 &&
>>> -		 encoder->port != PORT_A);
>>> +		 encoder->port != PORT_A));
>>>    }
>>>
>>>    static int dg2_max_source_rate(struct intel_dp *intel_dp)
>