Re: [PATCH 2/2] hw/display/xlnx_dp: Don't abort for unsupported graphics formats

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Hi,

On 6/11/25 15:52, Peter Maydell wrote:
> If the guest writes an invalid or unsupported value to the
> AV_BUF_FORMAT register, currently we abort().  Instead, log this as
> either a guest error or an unimplemented error and continue.
> 
> The existing code treats DP_NL_VID_CB_Y0_CR_Y1 as x8b8g8r8
> via a "case 0" that does not use the enum constant name for some
> reason; we leave that alone beyond adding a comment about the
> weird code.
> 
> Documentation of this register seems to be at:
> https://docs.amd.com/r/en-US/ug1087-zynq-ultrascale-registers/AV_BUF_FORMAT-DISPLAY_PORT-Register
> 
> Cc: qemu-stable@nongnu.org
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1415
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   hw/display/xlnx_dp.c | 53 +++++++++++++++++++++++++++++++++++++++-----
>   1 file changed, 48 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/display/xlnx_dp.c b/hw/display/xlnx_dp.c
> index c2bf692e7b1..d8119a56292 100644
> --- a/hw/display/xlnx_dp.c
> +++ b/hw/display/xlnx_dp.c
> @@ -665,14 +665,28 @@ static void xlnx_dp_change_graphic_fmt(XlnxDPState *s)
>       case DP_GRAPHIC_BGR888:
>           s->g_plane.format = PIXMAN_b8g8r8;
>           break;
> +    case DP_GRAPHIC_RGBA5551:
> +    case DP_GRAPHIC_RGBA4444:
> +    case DP_GRAPHIC_8BPP:
> +    case DP_GRAPHIC_4BPP:
> +    case DP_GRAPHIC_2BPP:
> +    case DP_GRAPHIC_1BPP:
> +        qemu_log_mask(LOG_UNIMP, "%s: unimplemented graphic format %u",
> +                      __func__,
> +                      s->avbufm_registers[AV_BUF_FORMAT] & DP_GRAPHIC_MASK);
> +        s->g_plane.format = PIXMAN_r8g8b8a8;
> +        break;
>       default:
> -        error_report("%s: unsupported graphic format %u", __func__,
> -                     s->avbufm_registers[AV_BUF_FORMAT] & DP_GRAPHIC_MASK);
> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid graphic format %u",
> +                      __func__,
> +                      s->avbufm_registers[AV_BUF_FORMAT] & DP_GRAPHIC_MASK);
> +        s->g_plane.format = PIXMAN_r8g8b8a8;
>           abort();

Don't we want to remove this abort() call?

Otherwise,

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

>       }