<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_REOPENED " title="REOPENED - [HSW] X server hang when toggling fullscreen in media player" href="https://bugs.freedesktop.org/show_bug.cgi?id=100162#c15">Comment # 15</a> on <a class="bz_bug_link bz_status_REOPENED " title="REOPENED - [HSW] X server hang when toggling fullscreen in media player" href="https://bugs.freedesktop.org/show_bug.cgi?id=100162">bug 100162</a> from <a class="email" href="mailto:thomas.lindroth@gmail.com" title="Thomas Lindroth <thomas.lindroth@gmail.com>"> Thomas Lindroth</a> <pre>I was looking in /sys for something and accidentally discovered that reading from /sys/kernel/debug/dri/0/i915_gem_pageflip can trigger the hang. The following content in i915_gem_pageflip will result in a hang: Flip queued on pipe A (plane A) Flip queued on blitter ring at seqno a9e95, next seqno a9e97 [current breadcrumb a9e96], completed? 1 Flip queued on frame 533858, (was ready on frame 0), now 533858 Stall check enabled, 1 prepares Current scanout address 0x00b80000 New framebuffer address 0x02780000 MMIO update completed? 0 No flip due on pipe B (plane B) Flip queued on pipe C (plane C) Flip queued on blitter ring at seqno a9e96, next seqno a9e97 [current breadcrumb a9e96], completed? 1 Flip queued on frame 533715, (was ready on frame 0), now 533715 Stall check enabled, 1 prepares Current scanout address 0x00b8f000 New framebuffer address 0x0278f000 MMIO update completed? 0 but this content will not hang: No flip due on pipe A (plane A) No flip due on pipe B (plane B) No flip due on pipe C (plane C) So basically reading from i915_gem_pageflip when there is a pageflip queued can cause the hang but like before the hang also happens when I'm not reading from /sys The hang is like before. I can move the mouse and use keyboard shortcuts but the screen is frozen. If I try switching to framebuffer it will come up after 60 sec. Using UXA instead of SNA or using modesetting will never hang. i915_gem_pageflip will always read "No flip due on pipe ..." for those. If I try to use a compositor like compton with modesetting there are still no hangs even though i915_gem_pageflip shows pageflips. I'm running kernel 4.4.110 now but I also tested 4.9.75 and it also hangs. The hang in 4.9.75 is worse because I couldn't move the mouse or switch to framebuffer. I had to sysrq reboot. Since I now have a deterministic way of triggering the hang (or a similar hang) it should be easier to test.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>