Re: xsysace.c oops on restart
From: Grant Likely <hidden>
Date: 2008-01-26 06:03:20
On 1/25/08, Jean-Samuel Chenard [off-list ref] wrote:
Hi Grant, I'm writing this e-mail directly to you before posting in the discussion forums because I found some issues with the xsysace.c driver. You are listed as the main author of the driver, so I'm assuming you might have a better clue than me as to what is happening.
Feel free to post to the mailing list regardless. It's better to have a public record of our discussions. I certainly have no problem with you pointing out issues with that driver in public. :-)
When I built kernel 2.6.23.9 or the latest from your git tree, if I use the new system ACE driver that you wrote, I cannot reboot without a Oops in the kernel. The message happens very late before the CPU is supposed to reboot. If I compile the kernel with the old Xilinx driver, I don't get the oops on restart.
Yeah; that definitely sounds like a driver bug.
Below are the details of the exception. The system is going down NOW! Sending SIGTERM to all processes Requesting system reboot [172545.229120] Restarting system. [172545.232346] <NULL> [172545.234663] Oops: Exception in kernel mode, sig: 8 [#1] [172545.239960] NIP: c7cb7e00 LR: c7cb7df0 CTR: 00000001 [172545.245003] REGS: c7cb7d40 TRAP: 2007df0 Not tainted (2.6.23.9-jsc-vanilla) [172545.252291] MSR: 00000000 <> CR: 00000010 XER: 000a00d2 [172545.257773] TASK =3D c02fb430[136] 'init' THREAD: c7cb6000 [172545.262976] GPR00: 3c303e5b 31373235 34352e32 32393132 305d2000 00000000 00000000 7fa41efc [172545.271442] GPR08: 00000000 fee1dead 28121969 00000000 c7cb7df0 c0016350 00000000 00000000 [172545.279902] GPR16: 00000001 00000000 c0170000 c019a464 c000b1f0 00607b83 00000000 00000000 [172545.288368] GPR24: 00000000 ffffffff 00000000 0002d030 00000001 c0024ccc 00000000 00000000 [172545.296999] NIP [c7cb7e00] 0xc7cb7e00 [172545.300747] LR [c7cb7df0] 0xc7cb7df0 [172545.304400] Call Trace: [172545.306925] Instruction dump: [172545.309965] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX [172545.317781] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
This traceback doesn't help much without knowing where 0xc7cb7e00 is in your kernel image. You could use gdb on the vmlinux image to figure it out, but it would be simpler to enable CONFIG_DEBUG_BUGVERBOSE and CONFIG_DEBUG_INFO and run it again. That should give you a more meaningful traceback. I've also got a rework patch for the sysace drive which makes it a bit more robust. I'll post it to the list shortly.
quoted hunk
The only modification I had to make in the xsysace.c to make it work on my ML-310 is change the width of the systemACE bus:@@ -1126,7 +1127,7 @@ static void __devexit ace_free(struct device *dev) static int __devinit ace_probe(struct platform_device *dev) { unsigned long physaddr =3D 0; - int bus_width =3D ACE_BUS_WIDTH_16; /* FIXME: should not be hard =
coded */
+ int bus_width =3D ACE_BUS_WIDTH_8; /* FIXME: should not be hard c=
oded */
int id =3D dev->id;
int irq =3D NO_IRQ;
int i;
I would prefer to use the new systemACE driver because it seems to be
faster (and the code is cleaner), but this oops on restart prevents me
from doing a lot of work remotely since I need to press the reset
button on my board. I get this error on both my ML-310 board and the
BEE2 machine I have at school. I guess I could investigate a bit more
by building the systemACE as a module and trying to load and unload it
to see if I can make it crash. It may not even be related to that
driver, but if I change to the older driver, I never get this problem.
Every time I use the new driver, the problem shows up and this is the
only setting that I change in the kernel. All the time, I have the
driver built into the kernel (not as a loadable module).
Also, thanks to your Wiki pages and discussions in the linux-ppc
groups, I managed to get my BEE2 to boot Linux 2.6 with all the
goodies. This is basically the only leftover issue with my system.
Let me know if you have some insights as why this could happen. I can
see if other people have seen a similar problem in the discussion
forums.
Regards,
Jean-Samuel
--
Ph.D. candidate
Integrated Microsystems Laboratory
McGill University, Montr=E9al, QC, CANADA
Web Page: http://chaos.ece.mcgill.ca--=20 Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd.