linux/drivers
Chris Wilson bcf9dcc1e6 drm/i915: Workaround hang with BSD and forcewake on SandyBridge
For reasons that are not apparent to anybody, 990bbdadab (drm/i915:
Group the GT routines together in both code and vtable) breaks the use
of the BitStream Decoder ring on SandyBridge. The active ingredient of
that patch is the conversion from a udelay(10) to a udelay(1) in the
busy-wait loop of waiting for the forcewake acknowledge. If we restore
that udelay(10) or insert another udelay(1) afterwards (or any wait
longer than 250ns) everything works again. An alternative is also to
remove any delay from the busy-wait loop.

Given that in the atomic sections we want to complete the wait as quick
as possible to avoid blocking the CPU for too long, it makes sense to
remove the delay altogether and simply spin on the exit condition until
it completes. So we replace the udelay(1) with cpu_relax().

Papers over regression from

commit 990bbdadab
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Jul 2 11:51:02 2012 -0300

    drm/i915: Group the GT routines together in both code and vtable

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=51738
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-08-06 10:43:29 +02:00
..
accessibility
acpi Merge branches 'bugfix-battery', 'bugfix-misc', 'bugfix-rafael', 'bugfix-turbostat', 'bugfix-video' and 'workaround-pss' into release 2012-06-04 00:48:41 -04:00
amba arm-soc: driver specific updates 2012-05-26 12:22:27 -07:00
ata Viresh has moved 2012-06-20 14:39:36 -07:00
atm solos-pci: Fix DMA support 2012-05-24 16:22:53 -04:00
auxdisplay
base Driver core and printk fixes for 3.5-rc4 2012-06-20 15:14:28 -07:00
bcma bcma: fix null pointer in bcma_core_pci_irq_ctl 2012-06-08 13:47:07 -04:00
block mtip32xx: Changes to sysfs entries 2012-05-31 08:46:50 +02:00
bluetooth Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-05-24 11:54:29 -07:00
cdrom
char agp/intel-agp: remove snb+ host bridge pciids 2012-06-25 21:10:35 +02:00
clk Viresh has moved 2012-06-20 14:39:36 -07:00
clocksource clocksource: sh_tmu: Use clockevents_config_and_register(). 2012-06-11 17:10:16 +09:00
connector
cpufreq
cpuidle
crypto arm-soc: clock driver changes 2012-05-26 12:42:29 -07:00
dca
devfreq Power management updates for 3.5 2012-05-23 14:07:06 -07:00
dio
dma Merge branch 'fixes' of git://git.infradead.org/users/vkoul/slave-dma 2012-06-20 22:12:52 -07:00
edac edac: Do alignment logic properly in edac_align_ptr() 2012-06-11 12:43:16 -03:00
eisa
extcon extcon: max8997: Add missing kfree for info->edev in max8997_muic_remove() 2012-06-18 16:30:42 -07:00
firewire IEEE 1394 (FireWire) subsystem updates post v3.4: 2012-05-24 12:57:47 -07:00
firmware
gpio gpio/samsung: fix the typo 'exynos5_xxx' instead of 'exonys5_xxx' 2012-06-03 21:21:01 -07:00
gpu drm/i915: Workaround hang with BSD and forcewake on SandyBridge 2012-08-06 10:43:29 +02:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-05-22 19:22:50 -07:00
hsi
hv Driver core pull for 3.5-rc1 2012-05-22 16:02:13 -07:00
hwmon hwmon fixes for 3.5-rc4 2012-06-21 13:40:40 -07:00
hwspinlock
i2c i2c: Add generic I2C multiplexer using pinctrl API 2012-06-04 16:49:43 +02:00
ide drivers/ide/ide-cs.c: adjust suspicious bit operation 2012-06-12 15:51:41 -07:00
idle
ieee802154
iio iio: drop wrong reference from Kconfig 2012-06-14 17:28:46 -07:00
infiniband Merge branches 'cma' and 'ocrdma' into for-linus 2012-06-24 04:59:59 -07:00
input i2c: Split I2C_M_NOSTART support out of I2C_FUNC_PROTOCOL_MANGLING 2012-05-30 10:55:34 +02:00
iommu iommu/amd: Fix deadlock in ppr-handling error path 2012-06-04 12:47:44 +02:00
isdn Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-05-24 11:54:29 -07:00
leds leds: Make LEDS_ASIC3 and LEDS_RENESAS_TPU depend on LEDS_CLASS=y 2012-06-12 10:56:25 +08:00
lguest
macintosh
md md: 2 fixes for 3.5-rc 2012-06-06 09:49:28 -07:00
media media: pms.c needs linux/slab.h 2012-06-20 22:10:08 -07:00
memory
memstick
message Merge branch 'akpm' (Andrew's patch-bomb) 2012-05-31 18:10:18 -07:00
mfd Viresh has moved 2012-06-20 14:39:36 -07:00
misc misc: mei: set WDIOF_ALARMONLY on mei watchdog 2012-06-13 15:34:31 -07:00
mmc Merge branch 'akpm' (Andrew's patch-bomb) 2012-06-20 14:41:57 -07:00
mtd kmsg - kmsg_dump() use iterator to receive log buffer content 2012-06-15 14:53:59 -07:00
net Fix typo in printed messages 2012-06-24 11:03:52 -07:00
nfc NFC: potential integer overflow problem in check_crc() 2012-05-25 11:16:16 -04:00
nubus
of Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2012-05-29 18:27:19 -07:00
oprofile
parisc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-05-22 19:22:50 -07:00
parport Driver core pull for 3.5-rc1 2012-05-22 16:02:13 -07:00
pci USB: add NO_D3_DURING_SLEEP flag and revert 151b612847 2012-06-13 13:11:39 -07:00
pcmcia
pinctrl Merge branch 'akpm' (Andrew's patch-bomb) 2012-06-20 14:41:57 -07:00
platform drivers/platform/x86/acerhdf.c: correct Boris' mail address 2012-06-07 14:43:55 -07:00
pnp
power A bunch of fixes for v3.5, nothing extraordinary. 2012-05-31 12:10:15 -07:00
pps
ps3
ptp Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-05-22 19:22:50 -07:00
rapidio rapidio/tsi721: add DMA engine support 2012-05-31 17:49:31 -07:00
regulator regulator: Change db8500-prcmu match names to reflect Device Tree 2012-06-17 18:27:49 +01:00
remoteproc remoteproc/omap: fix dev_err typo 2012-06-17 10:31:03 +03:00
rpmsg
rtc Merge branches 'bugfix-battery', 'bugfix-misc', 'bugfix-rafael', 'bugfix-turbostat', 'bugfix-video' and 'workaround-pss' into release 2012-06-04 00:48:41 -04:00
s390 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2012-05-31 10:51:10 -07:00
sbus
scsi SCSI fixes on 20120614 2012-06-15 17:39:32 -07:00
sfi
sh sh: intc: Kill off special reservation interface. 2012-05-22 19:07:55 +09:00
sn
spi SPI: fix over-eager devm_xxx() conversion 2012-06-18 11:27:04 +01:00
ssb
staging drm: Make the .mode_fixup() operations mode argument a const pointer 2012-07-19 21:52:38 -04:00
target target: Return error to initiator if SET TARGET PORT GROUPS emulation fails 2012-06-12 20:12:25 -07:00
tc
thermal
tty Serial driver fixes for 3.5-rc4 2012-06-20 15:13:13 -07:00
uio
usb USB: fix gathering of interface associations 2012-06-14 17:13:34 -07:00
uwb
vhost
video fbdev fixes for 3.5 2012-06-16 16:59:05 -07:00
virt
virtio virtio-mmio: Devices parameter parsing 2012-05-22 12:16:15 +09:30
vlynq
vme
w1 arm-soc: clock driver changes 2012-05-26 12:42:29 -07:00
watchdog Viresh has moved 2012-06-20 14:39:36 -07:00
xen Five bug-fixes: 2012-06-15 17:17:15 -07:00
zorro
Kconfig Staging tree pull request for 3.5-rc1 2012-05-22 16:34:21 -07:00
Makefile arm-soc: driver specific updates 2012-05-26 12:22:27 -07:00