Re: [PATCH] ESP driver

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



David Miller wrote:
From: BERTRAND_Joël <joel.bertrand@xxxxxxxxxxx>
Date: Mon, 18 Feb 2008 22:34:25 +0100

I think I have found a bug in esp_scsi.c. Without this patch, my SS20/SMP was not able to rebuild its internal raid1 volume due to esp0 DMA errors. With the following patch, same workstation is building a kernel, doing a rsync (between two local directories) and rebuilding a 26 GB raid1 volume without any trouble.

Signed-off-by: BERTRAND Joel <joel.bertrand@xxxxxxxxxxx>

It may correct your problem for some reason, but this change
is not correct (and your email client or your editor used
spaces instead of tab characters in your change).  The FAS100A
implements the ESP_STAT_INTR bit correctly.

If the FAS100A needed this change, you would get spurious IRQs or
other state machine errors, not DMA errors.

I think your change merely changes timings, making the DMA problem
harder to trigger.

I'm sorry I don't have more desirable feedback for your patch, but
it's the best I can do :-)

	David,

Only one question. For you, where can I find this bug ? In arch/sparc, in shared code or in ESP driver itself ?

I have seen that DMA errors were allways followed by some ESP resets (I think because I can see an AUTOSENSE command on console) but this ESP reset command aborts or does not avoid ESP_STAT_INTR flag in esp->sreg. Why not reset command does not clear this flag ? I'm not sure that it's a mistake, but I don't understand why this flag remains set.

You said that my patch makes problem harder to trigger. Maybe, but I'm pretty sure than this bug is close from this ESP_STAT_INTR flag that is not cleared for some reasons on SS20. I have tested my quick and dirty patch all night with 6 disks (two internal, four external and a CDROM reader). Configuration :

/dev/sda1 + /dev/sdb1 => /boot
/dev/sda2 + /dev/sdb2 => swap
/dev/sda4 + /dev/sdb4 => /
/dev/sda8 + /dev/sdb8 => /opt
/dev/sdc1 + /dev/sdd1 + /dev/sde1 + /dev/sdf1 => /export/home (raid5)

and I have stressed ESP chip without any trouble.

	Regards,

	JKB
-
To unsubscribe from this list: send the line "unsubscribe sparclinux" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Kernel Development]     [DCCP]     [Linux ARM Development]     [Linux]     [Photo]     [Yosemite Help]     [Linux ARM Kernel]     [Linux SCSI]     [Linux x86_64]     [Linux Hams]

  Powered by Linux