Re: new Areca driver in 2.6.16-rc6-mm2 appears to be broken

["erich" <erich@areca.com.tw>]

Dear Randy.Dunlap,

Thanks for your new update information.
The ARCMSR_MAX_XFER_SECTORS has bug if its value equal to 4096.
I had change ARCMSR_MAX_XFER_SECTORS of arcmsr linux driver into 512 at last 
driver version.
I will find out the solution and implement it into 4096.

Best Regards
Erich Chen

----- Original Message ----- 
From: "Randy.Dunlap" <rdunlap@xenotime.net>
To: "erich" <erich@areca.com.tw>
Cc: <dax@gurulabs.com>; <billion.wu@areca.com.tw>; <viro@ftp.linux.org.uk>; 
<akpm@osdl.org>; <matti.aarnio@zmailer.org>; <linux-kernel@vger.kernel.org>; 
<James.Bottomley@steeleye.com>; <ccaputo@alt.net>
Sent: Wednesday, April 26, 2006 12:02 AM
Subject: Re: new Areca driver in 2.6.16-rc6-mm2 appears to be broken


> On Tue, 25 Apr 2006 16:45:18 +0800 erich wrote:
>
>> Dear Randy.Dunlap,
>>
>> If it is true, I will add sg count check in arcmsr.
>> Driver report : host->sg_tablesize=ARCMSR_MAX_SG_ENTRIES to linux scsi 
>> host
>> layer.
>> But got an incorrect request of sg list count from .queuecommand.
>> Could you tell me which value of ARCMSR_MAX_XFER_SECTORS (4096/512)?
>
> Hi Erich,
> I didn't see 70 sg pieces while using the arcmsr driver, it was
> while testing another driver.  Sorry if that wasn't clear.
>
> Driver setting host->sg_tablesize should be good enough according
> to Documentation/scsi/scsi_mid_low_api.txt .  Are you seeing problems
> with that?  and I don't understand your last question about
> ARCMSR_MAX_XFER_SECTORS.
>
>
>> Best Regards
>> Erich chen
>>
>> ----- Original Message ----- 
>> From: "Randy.Dunlap" <rdunlap@xenotime.net>
>> To: "erich" <erich@areca.com.tw>
>> Cc: <axboe@suse.de>; <dax@gurulabs.com>; <billion.wu@areca.com.tw>;
>> <viro@ftp.linux.org.uk>; <akpm@osdl.org>; <matti.aarnio@zmailer.org>;
>> <linux-kernel@vger.kernel.org>; <James.Bottomley@steeleye.com>;
>> <ccaputo@alt.net>
>> Sent: Thursday, April 20, 2006 11:38 PM
>> Subject: Re: new Areca driver in 2.6.16-rc6-mm2 appears to be broken
>>
>>
>> > On Thu, 20 Apr 2006 16:11:04 +0800 erich wrote:
>> >
>> >> Dear Dear Jens Axboe,
>> >>
>> >> Thanks for your notification and advice.
>> >> Areca's firmware has max sg entries of 38 limit.
>> >> In my debug driver I had add this condition check.
>> >> But no one request more than 38 sg.
>> >
>> > Yesterday I saw a request with 70 sg pieces.  It was while
>> > running mkfs.ext3 .
>> >
>> >> Both transfer length all have a lot of requests equal with 38 sg.
>> >> But why it ocur only at 4096 sectors?
>> >> If the /sys/block/sda/queue/max_sectors_kb equal 256 all operation
>> >> running
>> >> well.
>> >> But if I modify it more than 256, the bug appeared.
>> >> I  will do more research about why there were a lot of requests equal
>> >> with
>> >> 38 sg in all file system.
>> >> And only it ocur at the volume that format with mkfs.ext2.
>> >> Thanks again.
>> >>
>> >> Best Regards
>> >> Erich Chen
>> >>
>> >> ----- Original Message ----- 
>> >> From: "Jens Axboe" <axboe@suse.de>
>> >> To: "erich" <erich@areca.com.tw>
>> >> Cc: <dax@gurulabs.com>; <billion.wu@areca.com.tw>; "Al Viro"
>> >> <viro@ftp.linux.org.uk>; "Andrew Morton" <akpm@osdl.org>; 
>> >> "Randy.Dunlap"
>> >> <rdunlap@xenotime.net>; "Matti Aarnio" <matti.aarnio@zmailer.org>;
>> >> <linux-kernel@vger.kernel.org>; "James Bottomley"
>> >> <James.Bottomley@steeleye.com>; "Chris Caputo" <ccaputo@alt.net>
>> >> Sent: Thursday, April 20, 2006 2:42 PM
>> >> Subject: Re: new Areca driver in 2.6.16-rc6-mm2 appears to be broken
>> >>
>> >>
>> >> > On Thu, Apr 20 2006, erich wrote:
>> >> >> Dear Jens Axboe,
>> >> >>
>> >> >> I  do "fsck -fy /dev/sda1" on driver MAX_XFER_SECTORS 512.
>> >> >> The file system was not clean.
>> >> >> I attach mesg.txt for you refer to.
>> >> >>
>> >> >> =====================================
>> >> >> == boot with driver MAX_XFER_SECTORS 4096
>> >> >> =====================================
>> >> >> #mkfs.ext2 /dev/sda1
>> >> >> #reboot
>> >> >> =====================================
>> >> >> == boot with driver MAX_XFER_SECTORS 512
>> >> >> =====================================
>> >> >> #fsck -fy /dev/sda1
>> >> >> /dev/sda1:clean,.............
>> >> >> #reboot
>> >> >> =====================================
>> >> >> == boot with driver MAX_XFER_SECTORS 4096
>> >> >> =====================================
>> >> >> #mount /dev/sda1 /mnt/sda1
>> >> >> #cp /root/aa /mnt/sda1
>> >> >> #reboot
>> >> >> =====================================
>> >> >> == boot with driver MAX_XFER_SECTORS 512
>> >> >> =====================================
>> >> >> #fsck -fy /dev/sda1
>> >> >> /dev/sda1: no clean,........and dump message such as the attach 
>> >> >> file
>> >> >> mesg.txt.
>> >> >
>> >> > So the conclusion is that your driver and/or hardware corrupts data
>> >> > when
>> >> > you set MAX_XFER_SECTORS too high. I can't help you anymore with 
>> >> > this,
>> >> > you should be in the best position to debug the driver and/or 
>> >> > hardware
>> >> > :-)
>> >> >
>> >> > It could be that the higher setting just exposes another transfer
>> >> > setting bug, like maximum number of segments or segment size, etc.
>> >> >
>> >> > -- 
>> >> > Jens Axboe
>> >> >
>> >>
>> >>
>> >
>> >
>> > ---
>> > ~Randy
>>
>>
>
>
> ---
> ~Randy