Witness warnings regarding DRM i915

Hello,

I am running -CURRENT as of June 5th on an Dell Inspiron 510m laptop
which features 855GM graphics. When I load the corresponding kernel
module (i915.ko), I get the following messages from witness:

xclusive sleep mutex drm device r = 0 (0xc29c94d4) locked _at_ /usr/src/sys/modules/drm/drm/../../../dev/drm/drm_drv.c:904
stack backtrace:
kdb_backtrace(c0b3f46c,d5e81a18,1,26c,c2b608b0) at kdb_backtrace+0x2e
witness_warn(5,0,c0a2158b,c0a0be34,c0aaee40) at witness_warn+0x1d3
uma_zalloc_arg(c146ad20,0,102,c146c800,c2b608b0) at uma_zalloc_arg+0x5c
malloc(2c,c0aaee40,102,f,c2f5bacc) at malloc+0xda
sysctl_add_oid(c2f5bacc,c2b608b0,ffffffff,c0a2953e,80000002) at sysctl_add_oid+0x97
alloc_bounce_zone(c2f5b700,c0aabba0,101,0,c28619f0) at alloc_bounce_zone+0x2f0
bus_dma_tag_create(0,1000,0,ffffffff,ffffffff) at bus_dma_tag_create+0x195
drm_pci_alloc(c29c9400,1000,1000,ffffffff,c29c94d4) at drm_pci_alloc+0xa3
i915_dma_init(c2949c00,80446440,c2f5b600,3,c2d2e510) at i915_dma_init+0x377
drm_ioctl(c2949c00,80446440,c2f5b600,3,c2d2e510) at drm_ioctl+0x1af
giant_ioctl(c2949c00,80446440,c2f5b600,3,c2d2e510) at giant_ioctl+0x56
devfs_ioctl_f(c2c863a8,80446440,c2f5b600,c2f1e880,c2d2e510) at devfs_ioctl_f+0xe7
ioctl(c2d2e510,d5e81d04,c,445,c) at ioctl+0x45d
syscall(2830003b,2830003b,bfbf003b,0,8213000) at syscall+0x313
Xint0x80_syscall() at Xint0x80_syscall+0x1f
--- syscall (54, FreeBSD ELF32, ioctl), eip = 0x282f0fd3, esp = 0xbfbfea4c, ebp = 0xbfbfea68 ---

malloc(M_WAITOK) of "16", forcing M_NOWAIT with the following non-sleepable locks held:
exclusive sleep mutex drm device r = 0 (0xc29c94d4) locked _at_ /usr/src/sys/modules/drm/drm/../../../dev/drm/drm_drv.c:904
stack backtrace:
kdb_backtrace(c0b3f46c,d5e81a18,1,40,c2b608b0) at kdb_backtrace+0x2e
witness_warn(5,0,c0a2158b,c09e3a4e,c070f482) at witness_warn+0x1d3
uma_zalloc_arg(c146a960,0,2,c146c700,c2b608b0) at uma_zalloc_arg+0x5c
malloc(e,c0aaee40,2,d,c2f5bacc) at malloc+0xda
sysctl_add_oid(c2f5bacc,c2b608b0,ffffffff,c0a2953e,80000002) at sysctl_add_oid+0xd8
alloc_bounce_zone(c2f5b700,c0aabba0,101,0,c28619f0) at alloc_bounce_zone+0x2f0
bus_dma_tag_create(0,1000,0,ffffffff,ffffffff) at bus_dma_tag_create+0x195
drm_pci_alloc(c29c9400,1000,1000,ffffffff,c29c94d4) at drm_pci_alloc+0xa3
i915_dma_init(c2949c00,80446440,c2f5b600,3,c2d2e510) at i915_dma_init+0x377
drm_ioctl(c2949c00,80446440,c2f5b600,3,c2d2e510) at drm_ioctl+0x1af
giant_ioctl(c2949c00,80446440,c2f5b600,3,c2d2e510) at giant_ioctl+0x56
devfs_ioctl_f(c2c863a8,80446440,c2f5b600,c2f1e880,c2d2e510) at devfs_ioctl_f+0xe7
ioctl(c2d2e510,d5e81d04,c,445,c) at ioctl+0x45d
syscall(2830003b,2830003b,bfbf003b,0,8213000) at syscall+0x313
Xint0x80_syscall() at Xint0x80_syscall+0x1f
--- syscall (54, FreeBSD ELF32, ioctl), eip = 0x282f0fd3, esp = 0xbfbfea4c, ebp = 0xbfbfea68 ---

Regards,
-- 
Julian Stecklina

Being really good at C++ is like being really good at using rocks to
sharpen sticks. - Thant Tessman