<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - [BDW] [Bisected] Absolute constant buffers break VAAPI in mpv" href="https://bugs.freedesktop.org/show_bug.cgi?id=102774#c18">Comment # 18</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - [BDW] [Bisected] Absolute constant buffers break VAAPI in mpv" href="https://bugs.freedesktop.org/show_bug.cgi?id=102774">bug 102774</a> from <a class="email" href="mailto:kenneth@whitecape.org" title="Kenneth Graunke <kenneth@whitecape.org>"> Kenneth Graunke</a> <pre>(In reply to Maxim Baz from <a href="show_bug.cgi?id=102774#c17">comment #17</a>) > Hey Kenneth, has there been any traction on reverting and/or fixing the code > during the past 3 weeks? Looks like the thread your created [1] didn't > receive any attention whatsoever. > > [1]: > <a href="https://lists.freedesktop.org/archives/mesa-stable/2017-September/007116.html">https://lists.freedesktop.org/archives/mesa-stable/2017-September/007116.html</a> True that. I sent another patch to revert it off of master last week, which stirred up a bit of flames, and Kristian apparently convinced at least -some- kernel people that this needs to be fixed in the kernel. Whether anything will happen to that end, I have no idea. In the meantime, I've pushed my revert to master, with the appropriate marking for stable branches. Emil / Andres should pick it up for the 17.3 / 17.2 stable branches soon. Thanks for your patience, and sorry about this mess. :( Fixed in master with: commit 013d33122028f2492da90a03ae4bc1dab84c3ee9 Author: Kenneth Graunke <<a href="mailto:kenneth@whitecape.org">kenneth@whitecape.org</a>> Date: Thu Oct 19 14:38:30 2017 -0700 i965: Revert absolute mode for constant buffer pointers. The kernel doesn't initialize the value of the INSTPM or CS_DEBUG_MODE2 registers at context initialization time. Instead, they're inherited from whatever happened to be running on the GPU prior to first run of a new context. So, when we started setting these, other contexts in the system started inheriting our values. Since this controls whether 3DSTATE_CONSTANT_* takes a pointer or an offset, getting the wrong setting is fatal for almost any process which isn't expecting this. Unfortunately, VA-API and Beignet don't initialize this (nor does older Mesa), so they will die horribly if we start doing this. UXA and SNA don't use any push constants, so they are unaffected. Until we have some kind of solution to this problem, I'm going to revert this patch and abandon using the feature for now. It will lead to fewer pushed UBO ranges on Broadwell+, which may lead to lower performance, though I don't have any data on the impact. Cc: "17.3 17.2" <<a href="mailto:mesa-stable@lists.freedesktop.org">mesa-stable@lists.freedesktop.org</a>> Bugzilla: <a class="bz_bug_link bz_status_NEW " title="NEW - [BDW] [Bisected] Absolute constant buffers break VAAPI in mpv" href="show_bug.cgi?id=102774">https://bugs.freedesktop.org/show_bug.cgi?id=102774</a></pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>