Re: 2.6.24-rc4-mm1 and Very Slow PCMCIA Compact Flash

Zan Lynx wrote:

On Fri, 2007-12-07 at 15:22 -0800, Andrew Morton wrote:

quoted

On Fri, 07 Dec 2007 23:09:43 +0000
Zan Lynx [off-list ref] wrote:

quoted

On Fri, 2007-12-07 at 15:02 -0800, Andrew Morton wrote:

quoted

On Fri, 07 Dec 2007 20:38:24 +0000
Zan Lynx [off-list ref] wrote:

quoted

While I'm reporting problems I'll get this one out there.

I normally use a USB-2 memory card reader but I also have a PCMCIA
CompactFlash adapter that I use occasionally.  During the MM series
kernels 2.6.22 and 23 (I am pretty sure) this didn't work at all.  I
don't know about vanilla since I don't run that.

Now with MM kernels 2.6.24 rc1-4 the PCMCIA adapter works again, but I
only get read rates of 1.6 MB/s.  When it used to work in 2.6.20 I got
at least 16 MB/s.  The card itself is capable of 30+ in the USB-2
reader.

[cut]

quoted

Oh, OK.  Hopefully the ata guys can help out with this.

I don't know if it actually strictly a regression?  Did libata ever support
that device in any earlier kernels?

That could be why it didn't work for a few kernel versions.  I
reconfigured for a libata-only system a while back.  And, since I
usually use the USB-2 flash reader I didn't care much about the PCMCIA.

I will try reverting that patch later tonight, in a few hours.

It looks like pata_pcmcia is always PIO mode 0:

/**
 *	pcmcia_init_one		-	attach a PCMCIA interface
 *	@pdev: pcmcia device
 *
 *	Register a PCMCIA IDE interface. Such interfaces are PIO 0 and
 *	shared IRQ.
 */

I assume that with old IDE this would use ide_cs.c, but I'm drawing a blank on what modes that supports..

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Robert Hancock      Saskatoon, SK, Canada
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