[PATCH xserver 2/2] xf86RandR12: Fix XF86VidModeSetGamma triggering a BadImplementation error

[Alex Deucher]

On Sat, Sep 17, 2016 at 6:00 AM, Hans de Goede <hdegoede at redhat.com> wrote:
> Commit b4e46c0444bb ("xfree86: Hook up colormaps and RandR 1.2 gamma code")
> dropped the providing of a pScrn->ChangeGamma callback from the xf86RandR12
> code. Leaving pScrn->ChangeGamma NULL in most cases.
>
> This triggers the BadImplementation error in xf86ChangeGamma() :
>
>     if (pScrn->ChangeGamma)
>         return (*pScrn->ChangeGamma) (pScrn, gamma);
>
>     return BadImplementation;
>
> Which causes X-apps using XF86VidModeSetGamma to crash with a
> X protocol error.
>
> This commit fixes this by re-introducing the xf86RandR12ChangeGamma
> helper removed by the commit and adjusting it to work with the new
> combined palette / gamma code.
>
> Fixes: b4e46c0444bb ("xfree86: Hook up colormaps and RandR 1.2 gamma code")
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>

Not too familiar with the code in question, but it looks sane to me.
Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  hw/xfree86/modes/xf86RandR12.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
>
> diff --git a/hw/xfree86/modes/xf86RandR12.c b/hw/xfree86/modes/xf86RandR12.c
> index 36767b3..7b3b97b 100644
> --- a/hw/xfree86/modes/xf86RandR12.c
> +++ b/hw/xfree86/modes/xf86RandR12.c
> @@ -1916,6 +1916,34 @@ xf86RandR12LoadPalette(ScrnInfoPtr pScrn, int numColors, int *indices,
>      }
>  }
>
> +/*
> + * Compatibility with XF86VidMode's gamma changer.  This necessarily clobbers
> + * any per-crtc setup.  You asked for it...
> + */
> +
> +static int
> +xf86RandR12ChangeGamma(ScrnInfoPtr pScrn, Gamma gamma)
> +{
> +    RRCrtcPtr randr_crtc = xf86CompatRRCrtc(pScrn);
> +    int size;
> +
> +    if (!randr_crtc)
> +        return Success;
> +
> +    size = max(0, randr_crtc->gammaSize);
> +    if (!size)
> +        return Success;
> +
> +    init_one_component(randr_crtc->gammaRed, size, gamma.red);
> +    init_one_component(randr_crtc->gammaGreen, size, gamma.green);
> +    init_one_component(randr_crtc->gammaBlue, size, gamma.blue);
> +    xf86RandR12CrtcSetGamma(xf86ScrnToScreen(pScrn), randr_crtc);
> +
> +    pScrn->gamma = gamma;
> +
> +    return Success;
> +}
> +
>  static Bool
>  xf86RandR12EnterVT(ScrnInfoPtr pScrn)
>  {
> @@ -2115,6 +2143,7 @@ xf86RandR12Init12(ScreenPtr pScreen)
>      rp->rrProviderDestroy = xf86RandR14ProviderDestroy;
>
>      pScrn->PointerMoved = xf86RandR12PointerMoved;
> +    pScrn->ChangeGamma = xf86RandR12ChangeGamma;
>
>      randrp->orig_EnterVT = pScrn->EnterVT;
>      pScrn->EnterVT = xf86RandR12EnterVT;
> --
> 2.9.3
>
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