Re: [Mesa-dev] [PATCH 3/5] glx/dri3: Request non-vsynced Present for swapinterval zero. (v2)
Hi, On 12/04/2014 11:38 PM, Mario Kleiner wrote: On 12/04/2014 11:20 AM, Axel Davy wrote: On 02/12/2014 20:53, Mario Kleiner wrote : Restores proper immediate tearing swap behaviour for OpenGL bufferswap under DRI3/Present. + if (priv-swap_interval == 0) + options |= XCB_PRESENT_OPTION_ASYNC; + back-busy = 1; Currently under DRI3 glx, you'll get triple buffering behaviour. I agree this should not be the default, and your patches fixes that. Ideally a user option should be added to control triple buffering. The DRI2 implementation had a per-drawable swap_limit and corresponding server api to get and set it. I'm not sure atm. if it was ever exposed via mesa, but i think it wasn't. I agree i would be nice to have some control there. There is one more problem i noticed, of which i'm not yet sure if it is related to mesa's n-buffering and the way it dynamically adapts n, or some driver implementation bug, or some other weirdness, because intel and nouveau behave differently. If a client does multiple swapbuffers calls without any rendering inbetween, then something in the buffer management seems to get confused for the rest of the session, even if the client later behaves properly ie., draw - swap - draw - swap ... Could this be related to / explain also: https://bugs.freedesktop.org/show_bug.cgi?id=81204 ? (Another buffer swap related issue with DRI3 is bug 79715) - Eero Good case: During whole session: draw - swap - draw - swap ... Bad case: At least once: swap - swap For the rest of the session, even if you do regular draw-swap-draw-swap, at least under nouveau, you get proper display for a few frames, followed by some frame displayed which contains pixel trash, like from an uninitialized renderbuffer, then a few good frames - pixel trash and so on. First i thought it's unsynchronized rendering to a swap pending buffer, ie., buffer presented while still rendered to. But now i think it is a trash filled buffer presented every couple of frames. I didn't have time to track this one down, and probably won't have time to look into it atm. I just made sure that my application never does idle swaps, even if it only renders one useless pixel to keep mesa from freaking out. Could be a bug. Could be some assumption that gets broken in a rather confusing way due to the triple/n-buffering. If you add a comment above these lines, saying something like: It is possible to enable triple buffering behaviour by not using XCB_PRESENT_OPTION_ASYNC, but this should not be the default. I'll add it literally, because anything i write in comments tends to become a not very well written essay ;-). Or should i add a ...but this triple buffering should probably not be the default in future implementations but be made configurable by some new api? thanks, -mario You can add my Reviewed-by: Axel Davy axel.d...@ens.fr Axel Davy ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH 3/5] glx/dri3: Request non-vsynced Present for swapinterval zero. (v2)
On 02/12/2014 20:53, Mario Kleiner wrote : Restores proper immediate tearing swap behaviour for OpenGL bufferswap under DRI3/Present. + if (priv-swap_interval == 0) + options |= XCB_PRESENT_OPTION_ASYNC; + back-busy = 1; Currently under DRI3 glx, you'll get triple buffering behaviour. I agree this should not be the default, and your patches fixes that. Ideally a user option should be added to control triple buffering. If you add a comment above these lines, saying something like: It is possible to enable triple buffering behaviour by not using XCB_PRESENT_OPTION_ASYNC, but this should not be the default. You can add my Reviewed-by: Axel Davy axel.d...@ens.fr Axel Davy ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH 3/5] glx/dri3: Request non-vsynced Present for swapinterval zero. (v2)
On 12/04/2014 11:20 AM, Axel Davy wrote: On 02/12/2014 20:53, Mario Kleiner wrote : Restores proper immediate tearing swap behaviour for OpenGL bufferswap under DRI3/Present. + if (priv-swap_interval == 0) + options |= XCB_PRESENT_OPTION_ASYNC; + back-busy = 1; Currently under DRI3 glx, you'll get triple buffering behaviour. I agree this should not be the default, and your patches fixes that. Ideally a user option should be added to control triple buffering. The DRI2 implementation had a per-drawable swap_limit and corresponding server api to get and set it. I'm not sure atm. if it was ever exposed via mesa, but i think it wasn't. I agree i would be nice to have some control there. There is one more problem i noticed, of which i'm not yet sure if it is related to mesa's n-buffering and the way it dynamically adapts n, or some driver implementation bug, or some other weirdness, because intel and nouveau behave differently. If a client does multiple swapbuffers calls without any rendering inbetween, then something in the buffer management seems to get confused for the rest of the session, even if the client later behaves properly ie., draw - swap - draw - swap ... Good case: During whole session: draw - swap - draw - swap ... Bad case: At least once: swap - swap For the rest of the session, even if you do regular draw-swap-draw-swap, at least under nouveau, you get proper display for a few frames, followed by some frame displayed which contains pixel trash, like from an uninitialized renderbuffer, then a few good frames - pixel trash and so on. First i thought it's unsynchronized rendering to a swap pending buffer, ie., buffer presented while still rendered to. But now i think it is a trash filled buffer presented every couple of frames. I didn't have time to track this one down, and probably won't have time to look into it atm. I just made sure that my application never does idle swaps, even if it only renders one useless pixel to keep mesa from freaking out. Could be a bug. Could be some assumption that gets broken in a rather confusing way due to the triple/n-buffering. If you add a comment above these lines, saying something like: It is possible to enable triple buffering behaviour by not using XCB_PRESENT_OPTION_ASYNC, but this should not be the default. I'll add it literally, because anything i write in comments tends to become a not very well written essay ;-). Or should i add a ...but this triple buffering should probably not be the default in future implementations but be made configurable by some new api? thanks, -mario You can add my Reviewed-by: Axel Davy axel.d...@ens.fr Axel Davy ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH 3/5] glx/dri3: Request non-vsynced Present for swapinterval zero. (v2)
Mario Kleiner mario.kleiner...@gmail.com writes: Restores proper immediate tearing swap behaviour for OpenGL bufferswap under DRI3/Present. Cc: 10.3 10.4 mesa-sta...@lists.freedesktop.org v2: Add Frank Binns signed off by for his original earlier patch from April 2014, which is identical to this one, and Chris Wilsons reviewed tag from May 2014 for that patch, ergo also for this one. Signed-off-by: Frank Binns frank.bi...@imgtec.com Signed-off-by: Mario Kleiner mario.kleiner...@gmail.com Reviewed-by: Chris Wilson ch...@chris-wilson.co.uk --- src/glx/dri3_glx.c | 6 +- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/glx/dri3_glx.c b/src/glx/dri3_glx.c index 5796491..c53be1b 100644 --- a/src/glx/dri3_glx.c +++ b/src/glx/dri3_glx.c @@ -1518,6 +1518,7 @@ dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor, xcb_connection_t *c = XGetXCBConnection(dpy); struct dri3_buffer *back; int64_t ret = 0; + uint32_t options = XCB_PRESENT_OPTION_NONE; unsigned flags = __DRI2_FLUSH_DRAWABLE; if (flush) @@ -1557,6 +1558,9 @@ dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor, if (target_msc == 0) target_msc = priv-msc + priv-swap_interval * (priv-send_sbc - priv-recv_sbc); I'd add: /* From the GLX_EXT_swap_control spec: * * If interval is set to a value of 0, buffer swaps are not * synchronized to a video frame. */ Other than that, Reviewed-by: Eric Anholt e...@anholt.net + if (priv-swap_interval == 0) + options |= XCB_PRESENT_OPTION_ASYNC; + back-busy = 1; back-last_swap = priv-send_sbc; xcb_present_pixmap(c, @@ -1570,7 +1574,7 @@ dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor, None, /* target_crtc */ None, back-sync_fence, - XCB_PRESENT_OPTION_NONE, + options, target_msc, divisor, remainder, 0, NULL); -- 1.9.1 ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev signature.asc Description: PGP signature ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
[Mesa-dev] [PATCH 3/5] glx/dri3: Request non-vsynced Present for swapinterval zero. (v2)
Restores proper immediate tearing swap behaviour for OpenGL bufferswap under DRI3/Present. Cc: 10.3 10.4 mesa-sta...@lists.freedesktop.org v2: Add Frank Binns signed off by for his original earlier patch from April 2014, which is identical to this one, and Chris Wilsons reviewed tag from May 2014 for that patch, ergo also for this one. Signed-off-by: Frank Binns frank.bi...@imgtec.com Signed-off-by: Mario Kleiner mario.kleiner...@gmail.com Reviewed-by: Chris Wilson ch...@chris-wilson.co.uk --- src/glx/dri3_glx.c | 6 +- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/glx/dri3_glx.c b/src/glx/dri3_glx.c index 5796491..c53be1b 100644 --- a/src/glx/dri3_glx.c +++ b/src/glx/dri3_glx.c @@ -1518,6 +1518,7 @@ dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor, xcb_connection_t *c = XGetXCBConnection(dpy); struct dri3_buffer *back; int64_t ret = 0; + uint32_t options = XCB_PRESENT_OPTION_NONE; unsigned flags = __DRI2_FLUSH_DRAWABLE; if (flush) @@ -1557,6 +1558,9 @@ dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor, if (target_msc == 0) target_msc = priv-msc + priv-swap_interval * (priv-send_sbc - priv-recv_sbc); + if (priv-swap_interval == 0) + options |= XCB_PRESENT_OPTION_ASYNC; + back-busy = 1; back-last_swap = priv-send_sbc; xcb_present_pixmap(c, @@ -1570,7 +1574,7 @@ dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor, None, /* target_crtc */ None, back-sync_fence, - XCB_PRESENT_OPTION_NONE, + options, target_msc, divisor, remainder, 0, NULL); -- 1.9.1 ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
