Re: PIO with SSDs: needs a long DRQ-after-command timeout for WRITEs

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

 



On Wednesday 31 December 2008, Mark Lord wrote:
> Alan Cox wrote:
> >> So.. how long does libata and current IDE allow for initial DRQ assertion?
> >> It should probably be at least 500msec or more now.
> > 
> > I think we need to rewrite the PIO code paths to use disable/enable_irq
> > masking first before getting into adding long delays on PIO paths.
> ..
> 
> Yeah, that would be a good thing to do.

Unless shared IRQs come into the picture -- in such case disabling IRQ
for 0.5sec doesn't sound too sexy...

> But in the meanwhile, a longer timeout there doesn't affect
> any currently working systems -- they'll still wait only as long
> as they currently do.  And a longer timeout *will* enable these
> SSDs to work where they otherwise would not.
> 
> But perhaps the timeout is already long enough?
> I don't know where the current timeout is hiding in libata.  :)

When it comes to IDE the timeout is defined by WAIT_DRQ in <linux/ide.h>
and is currently set to 100ms.  There should be no problem with increasing
it if it would help to get some devices to work (please just send a patch).

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

[Index of Archives]     [Linux Filesystems]     [Linux SCSI]     [Linux RAID]     [Git]     [Kernel Newbies]     [Linux Newbie]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Samba]     [Device Mapper]

  Powered by Linux