[PATCH] drm: qxl: Delay entering atomic context during cursor update

[PATCH] drm: qxl: Delay entering atomic context during cursor update

[Gabriel Krisman Bertazi]

Hi Dave,

This is -rc material.  Once Gerd and others are happy with it, we should
queue for 4.12.

Thanks!

>8

qxl_release_map will enter an atomic context, but since we still need to
alloc memory for BOs, we better delay that until we have everything we
need, in case we need to sleep inside the allocation.  This avoids the
Sleep in atomic state below, which was reported by Mike.

 [   43.910362] BUG: sleeping function called from invalid context at mm/slab.h:432
 [   43.910955] in_atomic(): 1, irqs_disabled(): 0, pid: 2077, name: Xorg
 [   43.911472] Preemption disabled at:
 [   43.911478] [<ffffffffa02b1c45>] qxl_bo_kmap_atomic_page+0xa5/0x100 [qxl]
 [   43.912103] CPU: 0 PID: 2077 Comm: Xorg Tainted: G            E   4.12.0-master #38
 [ 43.912550] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
 rel-1.8.1-0-g4adadbd-20161202_174313-build11a 04/01/2014
 [   43.913202] Call Trace:
 [   43.913371]  dump_stack+0x65/0x89
 [   43.913581]  ? qxl_bo_kmap_atomic_page+0xa5/0x100 [qxl]
 [   43.913876]  ___might_sleep+0x11a/0x190
 [   43.914095]  __might_sleep+0x4a/0x80
 [   43.914319]  ? qxl_bo_create+0x50/0x190 [qxl]
 [   43.914565]  kmem_cache_alloc_trace+0x46/0x180
 [   43.914836]  qxl_bo_create+0x50/0x190 [qxl]
 [   43.915082]  ? refcount_dec_and_test+0x11/0x20
 [   43.915332]  ? ttm_mem_io_reserve+0x41/0xe0 [ttm]
 [   43.915595]  qxl_alloc_bo_reserved+0x37/0xb0 [qxl]
 [   43.915884]  qxl_cursor_atomic_update+0x8f/0x260 [qxl]
 [   43.916172]  ? drm_atomic_helper_update_legacy_modeset_state+0x1d6/0x210 [drm_kms_helper]
 [   43.916623]  drm_atomic_helper_commit_planes+0xec/0x230 [drm_kms_helper]
 [   43.916995]  drm_atomic_helper_commit_tail+0x2b/0x60 [drm_kms_helper]
 [   43.917398]  commit_tail+0x65/0x70 [drm_kms_helper]
 [   43.917693]  drm_atomic_helper_commit+0xa9/0x100 [drm_kms_helper]
 [   43.918039]  drm_atomic_commit+0x4b/0x50 [drm]
 [   43.918334]  drm_atomic_helper_update_plane+0xf1/0x110 [drm_kms_helper]
 [   43.918902]  __setplane_internal+0x19f/0x280 [drm]
 [   43.919240]  drm_mode_cursor_universal+0x101/0x1c0 [drm]
 [   43.919541]  drm_mode_cursor_common+0x15b/0x1d0 [drm]
 [   43.919858]  drm_mode_cursor2_ioctl+0xe/0x10 [drm]
 [   43.920157]  drm_ioctl+0x211/0x460 [drm]
 [   43.920383]  ? drm_mode_cursor_ioctl+0x50/0x50 [drm]
 [   43.920664]  ? handle_mm_fault+0x93/0x160
 [   43.920893]  do_vfs_ioctl+0x96/0x6e0
 [   43.921117]  ? __fget+0x73/0xa0
 [   43.921322]  SyS_ioctl+0x41/0x70
 [   43.921545]  entry_SYSCALL_64_fastpath+0x1a/0xa5
 [   43.922188] RIP: 0033:0x7f1145804bc7
 [   43.922526] RSP: 002b:00007ffcd3e50508 EFLAGS: 00003246 ORIG_RAX: 0000000000000010
 [   43.923367] RAX: ffffffffffffffda RBX: 0000000000000040 RCX: 00007f1145804bc7
 [   43.923852] RDX: 00007ffcd3e50540 RSI: 00000000c02464bb RDI: 000000000000000b
 [   43.924299] RBP: 0000000000000040 R08: 0000000000000040 R09: 000000000000000c
 [   43.924694] R10: 00007ffcd3e50340 R11: 0000000000003246 R12: 0000000000000018
 [   43.925128] R13: 00000000022bc390 R14: 0000000000000040 R15: 00007ffcd3e5062c

Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
---
 drivers/gpu/drm/qxl/qxl_display.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index 058340a002c2..4a340efd8ba6 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -575,8 +575,6 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
 	if (ret)
 		return;
 
-	cmd = (struct qxl_cursor_cmd *) qxl_release_map(qdev, release);
-
 	if (fb != old_state->fb) {
 		obj = to_qxl_framebuffer(fb)->obj;
 		user_bo = gem_to_qxl_bo(obj);
@@ -614,6 +612,7 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
 		qxl_bo_kunmap(cursor_bo);
 		qxl_bo_kunmap(user_bo);
 
+		cmd = (struct qxl_cursor_cmd *) qxl_release_map(qdev, release);
 		cmd->u.set.visible = 1;
 		cmd->u.set.shape = qxl_bo_physical_address(qdev,
 							   cursor_bo, 0);
@@ -624,6 +623,7 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
 		if (ret)
 			goto out_free_release;
 
+		cmd = (struct qxl_cursor_cmd *) qxl_release_map(qdev, release);
 		cmd->type = QXL_CURSOR_MOVE;
 	}
 
-- 
2.11.0

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

Re: [PATCH] drm: qxl: Delay entering atomic context during cursor update

[Gerd Hoffmann]

On Fri, 2017-05-19 at 14:58 -0300, Gabriel Krisman Bertazi wrote:
> Hi Dave,
> 
> This is -rc material.  Once Gerd and others are happy with it, we
> should
> queue for 4.12.
> 

Applied to drm-misc-fixes.

thanks,
  Gerd
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel