From 0d7f4c8658e00d30a1b0c3f2d803378eaa0717c7 Mon Sep 17 00:00:00 2001 From: Mario Kleiner Date: Fri, 5 Dec 2014 08:42:32 +0100 Subject: [PATCH] glx/dri3: Don't fail on glXSwapBuffersMscOML(dpy, window, 0, 0, 0) (v2) glXSwapBuffersMscOML() with target_msc=divisor=remainder=0 gets translated into target_msc=divisor=0 but remainder=1 by the mesa api. This is done for server DRI2 where there needs to be a way to tell the server-side DRI2ScheduleSwap implementation if a call to glXSwapBuffers() or glXSwapBuffersMscOML(dpy,window,0,0,0) was done. remainder = 1 was (ab)used as a flag to tell the server to select proper semantic. The DRI3/Present backend ignored this signalling, treated any target_msc=0 as glXSwapBuffers() request, and called xcb_present_pixmap with invalid divisor=0, remainder=1 combo. The present extension responded kindly to this with a BadValue error and dropped the request, but mesa's DRI3/Present backend doesn't check for error codes. From there on stuff went downhill quickly for the calling OpenGL client... This patch fixes the problem. v2: Change comments to be more clear, with reference to relevant spec, as suggested by Eric Anholt. Cc: "10.3 10.4" Signed-off-by: Mario Kleiner Reviewed-by: Axel Davy Reviewed-by: Eric Anholt --- src/glx/dri3_glx.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/src/glx/dri3_glx.c b/src/glx/dri3_glx.c index 3f5e64c2a1e..1ddc723d508 100644 --- a/src/glx/dri3_glx.c +++ b/src/glx/dri3_glx.c @@ -1560,11 +1560,24 @@ dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor, dri3_fence_reset(c, back); /* Compute when we want the frame shown by taking the last known successful - * MSC and adding in a swap interval for each outstanding swap request + * MSC and adding in a swap interval for each outstanding swap request. + * target_msc=divisor=remainder=0 means "Use glXSwapBuffers() semantic" */ ++priv->send_sbc; - if (target_msc == 0) + if (target_msc == 0 && divisor == 0 && remainder == 0) target_msc = priv->msc + priv->swap_interval * (priv->send_sbc - priv->recv_sbc); + else if (divisor == 0 && remainder > 0) { + /* From the GLX_OML_sync_control spec: + * + * "If = 0, the swap will occur when MSC becomes + * greater than or equal to ." + * + * Note that there's no mention of the remainder. The Present extension + * throws BadValue for remainder != 0 with divisor == 0, so just drop + * the passed in value. + */ + remainder = 0; + } /* From the GLX_EXT_swap_control spec: * -- 2.30.2