[Mesa-dev] [xorg 2/3] dri2: Pass swap-interval=0 ScheduleSwap requests to the ddx

[Fredrik Höglund]

On Monday 19 January 2015, Chris Wilson wrote:
> Allow the DDXes to opt-in and handle swap-interval=0 requests for
> themselves, for example by using asynchronous pageflips, rather than
> forcing a blit. This has the important side-effect of also
> disambiguating CopyRegion calls to always be client requests.
> 
> References: http://lists.x.org/archives/xorg-devel/2011-June/023102.html
> References: http://lists.x.org/archives/xorg-devel/2012-February/029336.html
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  hw/xfree86/dri2/dri2.c | 14 ++++++++++----
>  hw/xfree86/dri2/dri2.h |  5 ++++-
>  2 files changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
> index f9f594d..2c0367e 100644
> --- a/hw/xfree86/dri2/dri2.c
> +++ b/hw/xfree86/dri2/dri2.c
> @@ -114,6 +114,7 @@ typedef struct _DRI2Screen {
>      int fd;
>      unsigned int lastSequence;
>      int prime_id;
> +    int scheduleSwap0;
>  
>      DRI2CreateBufferProcPtr CreateBuffer;
>      DRI2DestroyBufferProcPtr DestroyBuffer;
> @@ -1116,8 +1117,8 @@ DRI2SwapBuffers(ClientPtr client, DrawablePtr pDraw, CARD64 target_msc,
>          return BadDrawable;
>      }
>  
> -    /* Old DDX or no swap interval, just blit */
> -    if (!ds->ScheduleSwap || !pPriv->swap_interval || pPriv->prime_id) {
> +    /* Old DDX or PRIME, just blit */
> +    if (!ds->scheduleSwap0 || pPriv->prime_id) {

I've been testing these patches with the radeon driver, and happened to
notice that it never pageflips. I think this line needs to be changed to
something along the lines of:

if (!ds->ScheduleSwap || (pPriv->swap_interval == 0 && !ds->scheduleSwap0) || pPriv->prime_id)

>          BoxRec box;
>          RegionRec region;
>  
> @@ -1139,7 +1140,9 @@ DRI2SwapBuffers(ClientPtr client, DrawablePtr pDraw, CARD64 target_msc,
>       * In the simple glXSwapBuffers case, all params will be 0, and we just
>       * need to schedule a swap for the last swap target + the swap interval.
>       */
> -    if (target_msc == 0 && divisor == 0 && remainder == 0) {
> +    if (pPriv->swap_interval == 0) {
> +	target_msc = 0;
> +    } else if (target_msc == 0 && divisor == 0 && remainder == 0) {
>          /* If the current vblank count of the drawable's crtc is lower
>           * than the count stored in last_swap_target from a previous swap
>           * then reinitialize last_swap_target to the current crtc's msc,
> @@ -1162,7 +1165,6 @@ DRI2SwapBuffers(ClientPtr client, DrawablePtr pDraw, CARD64 target_msc,
>           * number of pending swaps.
>           */
>          target_msc = pPriv->last_swap_target + pPriv->swap_interval;
> -
>      }
>  
>      pPriv->swapsPending++;
> @@ -1558,6 +1560,10 @@ DRI2ScreenInit(ScreenPtr pScreen, DRI2InfoPtr info)
>          ds->CopyRegion2 = info->CopyRegion2;
>      }
>  
> +    if (info->version >= 10) {
> +        ds->scheduleSwap0 = info->scheduleSwap0;
> +    }
> +
>      /*
>       * if the driver doesn't provide an AuthMagic function or the info struct
>       * version is too low, call through LegacyAuthMagic
> diff --git a/hw/xfree86/dri2/dri2.h b/hw/xfree86/dri2/dri2.h
> index 1e7afdd..1cf4288 100644
> --- a/hw/xfree86/dri2/dri2.h
> +++ b/hw/xfree86/dri2/dri2.h
> @@ -205,7 +205,7 @@ typedef int (*DRI2GetParamProcPtr) (ClientPtr client,
>  /**
>   * Version of the DRI2InfoRec structure defined in this header
>   */
> -#define DRI2INFOREC_VERSION 9
> +#define DRI2INFOREC_VERSION 10
>  
>  typedef struct {
>      unsigned int version;       /**< Version of this struct */
> @@ -252,6 +252,9 @@ typedef struct {
>      DRI2CreateBuffer2ProcPtr CreateBuffer2;
>      DRI2DestroyBuffer2ProcPtr DestroyBuffer2;
>      DRI2CopyRegion2ProcPtr CopyRegion2;
> +
> +    /* added in version 10 */
> +    int scheduleSwap0;
>  } DRI2InfoRec, *DRI2InfoPtr;
>  
>  extern _X_EXPORT Bool DRI2ScreenInit(ScreenPtr pScreen, DRI2InfoPtr info);
>