Re: [PATCH 4/7] drm/i915/gvt/display_helpers: Cast argument to enum pipe for pipe-offset macro

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 12/18/2025 3:55 PM, Jani Nikula wrote:
> On Thu, 18 Dec 2025, Ankit Nautiyal <ankit.k.nautiyal@intel.com> wrote:
>> TRANSCONF() expands via _MMIO_PIPE2, i.e., it uses pipe-based addressing.
>> In GVT, some call sites pass an enum transcoder to TRANSCONF(), which now
>> routes through INTEL_DISPLAY_DEVICE_PIPE_OFFSET() and ultimately calls
>> intel_display_device_pipe_offset(), whose parameter type is enum pipe.
>>
>> This results in -Werror=enum-conversion.
> And that's really why this should be squashed to the previous patch,
> with explanation in the commit message, as otherwise the previous one
> fails to build.
>
> I don't know, maybe could also add a FIXME comment about the cast?
> *shrug*

Alright, will add a fix me and merge this with the previous patch.

Regards,

Ankit

>
> BR,
> Jani.
>
>> To address this, cast the index to enum pipe in the GVT-side macro
>> override.
>>
>> This works for all cases as TRANSCODER_{A,B,C,D} all have 1:1 mapping to
>> PIPE_{A,B,C,D} except for TRANSCODER_EDP.
>>
>> There is one place which uses TRANSCONF() with TRANSCODER_EDP, which
>> appears to be incorrect. In any case, the cast preserves the previous
>> behaviour.
>>
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
>> ---
>>   drivers/gpu/drm/i915/gvt/display_helpers.h | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gvt/display_helpers.h b/drivers/gpu/drm/i915/gvt/display_helpers.h
>> index 97ebc92768fc..3af878e3d78e 100644
>> --- a/drivers/gpu/drm/i915/gvt/display_helpers.h
>> +++ b/drivers/gpu/drm/i915/gvt/display_helpers.h
>> @@ -17,8 +17,8 @@
>>   #ifdef INTEL_DISPLAY_DEVICE_PIPE_OFFSET
>>   #undef INTEL_DISPLAY_DEVICE_PIPE_OFFSET
>>   #endif
>> -#define INTEL_DISPLAY_DEVICE_PIPE_OFFSET(display, pipe) \
>> -	intel_display_device_pipe_offset((display), (pipe))
>> +#define INTEL_DISPLAY_DEVICE_PIPE_OFFSET(display, idx) \
>> +	intel_display_device_pipe_offset((display), (enum pipe)(idx))
>>   
>>   #ifdef INTEL_DISPLAY_DEVICE_TRANS_OFFSET
>>   #undef INTEL_DISPLAY_DEVICE_TRANS_OFFSET