From: Ameet Patil <ammubhai@gmail•com>
To: agnel juni <junijoseph@yahoo•co.in>
Cc: linuxppc-embedded@ozlabs•org
Subject: Re: System ACE driver - for 2.6 kernel - need help to understand xsa_thread
Date: Thu, 26 Oct 2006 09:00:48 +0100 [thread overview]
Message-ID: <45406B30.1050605@gmail.com> (raw)
In-Reply-To: <20061026003115.22528.qmail@web8408.mail.in.yahoo.com>
Hi Junita,
Its a hack really! When I was developing/porting the SysAce driver
to 2.6 I tried to maintain the code as is from the 2.4 kernel driver. In
doing so I found that there is a slight difference between the two
kernels. i.e. I am not sure why, but the sysace device can only handle
requests for 2 sectors at a time. This was fine in the 2.4 as the kernel
always requested 2 sectors. However, in 2.6 I found that this is
different: the requests are 8 secs. or more. I tried to fix this in vain
by changing several parameters of the driver during initialization.
Anyway, due to several issues I didn't try hard to fix it at that time.
Hence this hack: No matter how many sec. req. I get from the kernel, I
use a loop to req. only 2 secs. at a time. The xsa_device.req_done is
used as a flag and reset in the XSA IRQ IIRC.
If you find a better approach, please do update me. Hope this helps!
cheers,
-Ameet
agnel juni wrote:
>
> Hello all
>
> I am trying to understand the parameters that are sent through "cur_req"
> function used in funtion xsa_thread in System ACE driver.
>
> In xsa_thread function in the System ACE driver ,
>
> In 2.4 kernel:
> --------------------
> while ((stat = cur_req(&SysAce, sector,
> CURRENT->current_nr_sectors,
> CURRENT->buffer)) == XST_DEVICE_BUSY)
> xsa_short_delay();
>
>
> Where as in 2.6 kernel this is changed to
> ---------------------------------------------------------------
>
> for(i = xsa_cur_req->current_nr_sectors; i > 0; i-=2){
> xsa_device.req_done = 1;
> while ((stat = cur_req(&SysAce, sector,
> 2,
> buffer)) == XST_DEVICE_BUSY)
> xsa_short_delay();
> #endif
>
> Ameet , could you help me understand the impact of the parameters,
> especailly the 3rd paramter which is hardcoded in 2.6 kernel.It would be
> great if you could clarify this in regard to 'mount' command.
>
> Thanks in advance
> Junita
>
>
>
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prev parent reply other threads:[~2006-10-26 8:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <45300A50.2010000@vt.edu>
2006-10-14 17:35 ` Inquiring about your Linux 2.6.17.1 port to XUP Ameet Patil
2006-10-14 19:37 ` Gofast float point and 405ep Stelios Koroneos
2006-10-26 0:31 ` System ACE driver - for 2.6 kernel - need help to understand xsa_thread agnel juni
2006-10-26 8:00 ` Ameet Patil [this message]
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