[64studio-devel] [64 Studio] #131: Help package FreeBoB for Debian

[joel silvestre]

Le vendredi 19 janvier 2007 à 17:53 +0000, 64 Studio a écrit :
> #131: Help package FreeBoB for Debian
> ------------------------------+---------------------------------------------
>  Reporter:  daniel            |        Owner:  free
>      Type:  enhancement       |       Status:  new 
>  Priority:  high              |    Milestone:  2.0 
> Component:  packages          |      Version:      
>  Severity:  normal            |   Resolution:      
>  Keywords:  freebob firewire  |  
> ------------------------------+---------------------------------------------
> Comment (by free at 64studio.com):
> 
>  For this we probably need a tester with the proper hardware.. anyone
>  willing to have a go?
> 
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> 64studio-devel at 64studio.com
> http://lists.64studio.com/mailman/listinfo/64studio-devel


Hi,

Found  on the freebob-devel mailing list :

Cheers,
Joel


Jonathan Murphy wrote:
> Hi Folks,
> 
> I'm just wondering if the problem related to complete preemption has
> been fixed yet?

It is fixed as from 2.6.20-rc6-rt2. This means that the upcoming 2.6.20 
with -rt patches will work fine.

What you also can do is apply the attached patch to an earlier kernel 
(-rt patch it first). If it applies (probably with some offsets &
fuzz), 
the issue should be solved.

Pieter







pièce jointe
différences entre
fichiers
(kernel-2.6.19-rrt-deadlock-fix.patch)

Index: linux/include/linux/interrupt.h
===================================================================
--- linux.orig/include/linux/interrupt.h
+++ linux/include/linux/interrupt.h
@@ -328,10 +328,8 @@ static inline void tasklet_unlock(struct
        clear_bit(TASKLET_STATE_RUN, &(t)->state);
 }
 
-static inline void tasklet_unlock_wait(struct tasklet_struct *t)
-{
-       while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
-}
+extern void tasklet_unlock_wait(struct tasklet_struct *t);
+
 #else
 # define tasklet_trylock(t)            1
 # define tasklet_tryunlock(t)          1
Index: linux/kernel/softirq.c
===================================================================
--- linux.orig/kernel/softirq.c
+++ linux/kernel/softirq.c
@@ -20,6 +20,7 @@
 #include <linux/mm.h>
 #include <linux/notifier.h>
 #include <linux/percpu.h>
+#include <linux/delay.h>
 #include <linux/cpu.h>
 #include <linux/kthread.h>
 #include <linux/rcupdate.h>
@@ -656,6 +657,25 @@ void __init softirq_init(void)
        open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL);
 }
 
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
+
+void tasklet_unlock_wait(struct tasklet_struct *t)
+{
+       while (test_bit(TASKLET_STATE_RUN, &(t)->state)) {
+               /*
+                * Hack for now to avoid this busy-loop:
+                */
+#ifdef CONFIG_PREEMPT_RT
+               msleep(1);
+#else
+               barrier();
+#endif
+       }
+}
+EXPORT_SYMBOL(tasklet_unlock_wait);
+
+#endif
+
 static int ksoftirqd(void * __data)
 {
        struct sched_param param = { .sched_priority =
MAX_USER_RT_PRIO/2 };