Re: [PATCH 5/5] drm/i915/gvt/display_helpers: Cast argument to enum pipe for pipe-offset macro

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 15 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.
>
> 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.

Maybe the question to ask is if TRANSCONF() using _MMIO_PIPE2() is
correct or not?

BR,
Jani.

>
> 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 d11ebb03b946..fb75cc9f97cc 100644
> --- a/drivers/gpu/drm/i915/gvt/display_helpers.h
> +++ b/drivers/gpu/drm/i915/gvt/display_helpers.h
> @@ -21,8 +21,8 @@ struct display;
>  #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

-- 
Jani Nikula, Intel