Re: [patch] Real-Time Preemption, -RT-2.6.9-rc4-mm1-U8

[Rui Nuno Capela]

>>
>> for the sake of testing could you disable CONFIG_USB and see whether the
>> instability is truly directly related to the USB crash, as you suspect?
>> Such a kernel crash can often destabilize other parts of the kernel.
>>
>
> Just tested with CONFIG_USB off, and can't test the usb-storage crash, of
> course. However, jackd  is still freezing to death. No console, nor syslog
> output can be found. The system just dies sometime after some jack client
> is launched. Will try further.
>
> I'm on the way to test Thomas Gleixner's patch...
>

OK. Thomas patch solves the usb-storage crash, but I added an oneliner
change to it, to make it build. Corrected patch is appended.

Thanks.
-- 
rncbc aka Rui Nuno Capela
rncbc@xxxxxxxxxdiff -urN 2.6.9-rc4-mm1-RT-U8/drivers/usb/storage/scsiglue.c
2.6.9-rc4-mm1-RT-U8.1/drivers/usb/storage/scsiglue.c
--- 2.6.9-rc4-mm1-RT-U8/drivers/usb/storage/scsiglue.c	2004-10-12
09:41:44.000000000 +0200
+++ 2.6.9-rc4-mm1-RT-U8.1/drivers/usb/storage/scsiglue.c	2004-10-21
11:45:14.000000000 +0200
@@ -187,7 +187,7 @@
 	us->srb = srb;
 
 	/* wake up the process task */
-	up(&(us->sema));
+	complete(&(us->done));
 
 	return 0;
 }
diff -urN 2.6.9-rc4-mm1-RT-U8/drivers/usb/storage/usb.c
2.6.9-rc4-mm1-RT-U8.1/drivers/usb/storage/usb.c
--- 2.6.9-rc4-mm1-RT-U8/drivers/usb/storage/usb.c	2004-10-12
09:41:44.000000000 +0200
+++ 2.6.9-rc4-mm1-RT-U8.1/drivers/usb/storage/usb.c	2004-10-21
11:45:34.000000000 +0200
@@ -299,7 +299,7 @@
 
 	for(;;) {
 		US_DEBUGP("*** thread sleeping.\n");
-		if(down_interruptible(&us->sema))
+		if(wait_for_completion_interruptible(&us->done))
 			break;
 			
 		US_DEBUGP("*** thread awakened.\n");
@@ -845,7 +845,7 @@
 		scsi_unlock(us->host);
 		up(&us->dev_semaphore);
 
-		up(&us->sema);
+		complete(&us->done);
 		wait_for_completion(&us->notify);
 	}

@@ -941,7 +941,7 @@
 	}
 	memset(us, 0, sizeof(struct us_data));
 	init_MUTEX(&(us->dev_semaphore));
-	init_MUTEX_LOCKED(&(us->sema));
+	init_completion(&(us->done));
 	init_completion(&(us->notify));
 	init_waitqueue_head(&us->dev_reset_wait);
 	init_waitqueue_head(&us->scsi_scan_wait);
diff -urN 2.6.9-rc4-mm1-RT-U8/drivers/usb/storage/usb.h
2.6.9-rc4-mm1-RT-U8.1/drivers/usb/storage/usb.h
--- 2.6.9-rc4-mm1-RT-U8/drivers/usb/storage/usb.h	2004-10-12
09:41:44.000000000 +0200
+++ 2.6.9-rc4-mm1-RT-U8.1/drivers/usb/storage/usb.h	2004-10-21
11:45:13.000000000 +0200
@@ -159,8 +159,8 @@
 	dma_addr_t		iobuf_dma;
 
 	/* mutual exclusion and synchronization structures */
-	struct semaphore	sema;		 /* to sleep thread on   */
-	struct completion	notify;		 /* thread begin/end	 */
+	struct completion	done;   	 /* to sleep thread on   */
+	struct completion	notify; 	 /* thread begin/end	 */
 	wait_queue_head_t	dev_reset_wait;  /* wait during reset    */
 	wait_queue_head_t	scsi_scan_wait;	 /* wait before scanning */
 	struct completion	scsi_scan_done;	 /* scan thread end	 */