From c17c11831778d5ed948858ef4bb32058f5013094 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Fri, 11 Oct 2013 17:14:31 +0200 Subject: [PATCH] drm: remove preempt_disable() from drm_calc_vbltimestamp_from_scanoutpos() Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/3.12/patches-3.12.0-rt2.tar.xz Luis captured the following: | BUG: sleeping function called from invalid context at kernel/rtmutex.c:659 | in_atomic(): 1, irqs_disabled(): 0, pid: 517, name: Xorg | 2 locks held by Xorg/517: | #0: | ( | &dev->vbl_lock | ){......} | , at: | [] drm_vblank_get+0x30/0x2b0 [drm] | #1: | ( | &dev->vblank_time_lock | ){......} | , at: | [] drm_vblank_get+0xb1/0x2b0 [drm] | Preemption disabled at: | [] i915_get_vblank_timestamp+0x45/0xa0 [i915] | CPU: 3 PID: 517 Comm: Xorg Not tainted 3.10.10-rt7+ #5 | Call Trace: | [] dump_stack+0x19/0x1b | [] __might_sleep+0xff/0x170 | [] rt_spin_lock+0x24/0x60 | [] i915_read32+0x27/0x170 [i915] | [] i915_pipe_enabled+0x31/0x40 [i915] | [] i915_get_crtc_scanoutpos+0x3e/0x1b0 [i915] | [] drm_calc_vbltimestamp_from_scanoutpos+0xf4/0x430 [drm] | [] i915_get_vblank_timestamp+0x45/0xa0 [i915] | [] drm_get_last_vbltimestamp+0x48/0x70 [drm] | [] drm_vblank_get+0x185/0x2b0 [drm] | [] drm_wait_vblank+0x83/0x5d0 [drm] | [] drm_ioctl+0x552/0x6a0 [drm] | [] do_vfs_ioctl+0x325/0x5b0 | [] SyS_ioctl+0x81/0xa0 | [] tracesys+0xdd/0xe2 After a longer thread it was decided to drop the preempt_disable()/ enable() invocations which were meant for -RT and Mario Kleiner looks for a replacement. Cc: stable-rt@vger.kernel.org Reported-By: Luis Claudio R. Goncalves Signed-off-by: Sebastian Andrzej Siewior --- drivers/gpu/drm/drm_irq.c | 7 ------- 1 file changed, 7 deletions(-) --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -628,11 +628,6 @@ int drm_calc_vbltimestamp_from_scanoutpo * code gets preempted or delayed for some reason. */ for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) { - /* Disable preemption to make it very likely to - * succeed in the first iteration even on PREEMPT_RT kernel. - */ - preempt_disable(); - /* Get system timestamp before query. */ stime = ktime_get(); @@ -644,8 +639,6 @@ int drm_calc_vbltimestamp_from_scanoutpo if (!drm_timestamp_monotonic) mono_time_offset = ktime_get_monotonic_offset(); - preempt_enable(); - /* Return as no-op if scanout query unsupported or failed. */ if (!(vbl_status & DRM_SCANOUTPOS_VALID)) { DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",