Hello,
actually I have wanted to write to this list about NVIDIA-drivers for
some time and will use this opportunity.
Generally, it is obviously preferable to use the nouveau-driver if
possible which is working just fine. At our institute however, we need
to use the rt-patch in combination with the proprietary NVIDIA driver as
we need CUDA-support combined with low-latency control (e.g. for visual
servoing). And I am sure we are not the only ones requiring this
combination.
We have been using the 2.6.33-rt29 for some time now without any issues
and with very satisfactory latency. This required a small patch to the
NVIDIA-driver (there is a check for PREEMPT_RT) as atomic_spin* was
renamed to raw_spin* in one of the 2.6-rt-patches.
3.0-rt requires an additional slight modification as CONFIG_PREEMPT_RT
is not defined anymore and we must check instead for
CONFIG_PREEMPT_RT_FULL to decide whether to use raw spin_locks. Using
this patch it is then not necessary to change any EXPORT_SYMBOL_GPL to
EXPORT_SYMBOL in the kernel as was proposed in some other threads here.
You can find the patches for the nvidia-driver for 2.6.33-rt and 3.0-rt
below.
Unfortunately, with 3.0-rt and the nvidia-driver we get complete system
freezes when starting X on several different hardware setups (a few
systems work fine). This is certainly caused by this combination. When
using the nouveau-driver everything works fine.
I tested this with rt13 through rt20 and will check with the current
version tomorrow. If it still fails I will put together a list of
working vs. non-working hardware setups.
Unfortunately, apart from that I am not sure how to debug this issue, as
the complete system freezes (including the serial console) and I can't
find any suspicious messages in the logs. Any ideas?
Btw, changing EXPORT_SYMBOL_GPL to EXPORT_SYMBOL for
migrate_enable/disable, ... and then using the non-raw spinlocks results
in exactly the same behavior.
Best Regards,
Thomas Schauss
====================================================================
Patch for 3.0-rt:
--- a/nv-linux.h 2011-10-26 13:35:32.866579965 +0200
+++ b/nv-linux.h 2011-10-26 13:35:47.265117607 +0200
@@ -262,17 +262,17 @@
#endif
#endif
-#if defined(CONFIG_PREEMPT_RT)
-typedef atomic_spinlock_t nv_spinlock_t;
-#define NV_SPIN_LOCK_INIT(lock) atomic_spin_lock_init(lock)
-#define NV_SPIN_LOCK_IRQ(lock) atomic_spin_lock_irq(lock)
-#define NV_SPIN_UNLOCK_IRQ(lock) atomic_spin_unlock_irq(lock)
-#define NV_SPIN_LOCK_IRQSAVE(lock,flags)
atomic_spin_lock_irqsave(lock,flags)
+#if defined(CONFIG_PREEMPT_RT_FULL)
+typedef raw_spinlock_t nv_spinlock_t;
+#define NV_SPIN_LOCK_INIT(lock) raw_spin_lock_init(lock)
+#define NV_SPIN_LOCK_IRQ(lock) raw_spin_lock_irq(lock)
+#define NV_SPIN_UNLOCK_IRQ(lock) raw_spin_unlock_irq(lock)
+#define NV_SPIN_LOCK_IRQSAVE(lock,flags) raw_spin_lock_irqsave(lock,flags)
#define NV_SPIN_UNLOCK_IRQRESTORE(lock,flags) \
- atomic_spin_unlock_irqrestore(lock,flags)
-#define NV_SPIN_LOCK(lock) atomic_spin_lock(lock)
-#define NV_SPIN_UNLOCK(lock) atomic_spin_unlock(lock)
-#define NV_SPIN_UNLOCK_WAIT(lock) atomic_spin_unlock_wait(lock)
+ raw_spin_unlock_irqrestore(lock,flags)
+#define NV_SPIN_LOCK(lock) raw_spin_lock(lock)
+#define NV_SPIN_UNLOCK(lock) raw_spin_unlock(lock)
+#define NV_SPIN_UNLOCK_WAIT(lock) raw_spin_unlock_wait(lock)
#else
typedef spinlock_t nv_spinlock_t;
#define NV_SPIN_LOCK_INIT(lock) spin_lock_init(lock)
@@ -854,8 +854,8 @@
return ret;
}
-#if defined(CONFIG_PREEMPT_RT)
-#define NV_INIT_MUTEX(mutex) semaphore_init(mutex)
+#if defined(CONFIG_PREEMPT_RT_FULL)
+#define NV_INIT_MUTEX(mutex) sema_init(mutex,1)
#else
#if !defined(__SEMAPHORE_INITIALIZER) &&
defined(__COMPAT_SEMAPHORE_INITIALIZER)
#define __SEMAPHORE_INITIALIZER __COMPAT_SEMAPHORE_INITIALIZER
====================================================================
Patch for 2.6.33-rt:
--- a/nv-linux.h 2011-10-28 10:31:47.416915958 +0200
+++ b/nv-linux.h 2011-10-28 10:32:48.592195509 +0200
@@ -263,16 +263,16 @@
#endif
#if defined(CONFIG_PREEMPT_RT)
-typedef atomic_spinlock_t nv_spinlock_t;
-#define NV_SPIN_LOCK_INIT(lock) atomic_spin_lock_init(lock)
-#define NV_SPIN_LOCK_IRQ(lock) atomic_spin_lock_irq(lock)
-#define NV_SPIN_UNLOCK_IRQ(lock) atomic_spin_unlock_irq(lock)
-#define NV_SPIN_LOCK_IRQSAVE(lock,flags)
atomic_spin_lock_irqsave(lock,flags)
+typedef raw_spinlock_t nv_spinlock_t;
+#define NV_SPIN_LOCK_INIT(lock) raw_spin_lock_init(lock)
+#define NV_SPIN_LOCK_IRQ(lock) raw_spin_lock_irq(lock)
+#define NV_SPIN_UNLOCK_IRQ(lock) raw_spin_unlock_irq(lock)
+#define NV_SPIN_LOCK_IRQSAVE(lock,flags) raw_spin_lock_irqsave(lock,flags)
#define NV_SPIN_UNLOCK_IRQRESTORE(lock,flags) \
- atomic_spin_unlock_irqrestore(lock,flags)
-#define NV_SPIN_LOCK(lock) atomic_spin_lock(lock)
-#define NV_SPIN_UNLOCK(lock) atomic_spin_unlock(lock)
-#define NV_SPIN_UNLOCK_WAIT(lock) atomic_spin_unlock_wait(lock)
+ raw_spin_unlock_irqrestore(lock,flags)
+#define NV_SPIN_LOCK(lock) raw_spin_lock(lock)
+#define NV_SPIN_UNLOCK(lock) raw_spin_unlock(lock)
+#define NV_SPIN_UNLOCK_WAIT(lock) raw_spin_unlock_wait(lock)
#else
typedef spinlock_t nv_spinlock_t;
#define NV_SPIN_LOCK_INIT(lock) spin_lock_init(lock)
@@ -855,7 +855,7 @@
}
#if defined(CONFIG_PREEMPT_RT)
-#define NV_INIT_MUTEX(mutex) semaphore_init(mutex)
+#define NV_INIT_MUTEX(mutex) sema_init(mutex,1)
#else
#if !defined(__SEMAPHORE_INITIALIZER) &&
defined(__COMPAT_SEMAPHORE_INITIALIZER)
#define __SEMAPHORE_INITIALIZER __COMPAT_SEMAPHORE_INITIALIZER
begin:vcard
fn:Thomas Schauss
n:Schauss;Thomas
org:Technische Universitaet Muenchen (TUM);Institute of Automatic Control Engineering (LSR)
adr:;;Theresienstr. 90;Munich;;80333;Germany
email;internet:schauss@xxxxxx
title:Dipl.-Ing. (Univ.)
tel;work:+49 89 289 23406
tel;fax:+49 89 289 28340
url:http://www.lsr.ei.tum.de
version:2.1
end:vcard
