2.6.24-rc4-mm1 and Very Slow PCMCIA Compact Flash

Robert Hancock hancockr at shaw.ca
Fri Dec 7 23:47:57 EST 2007

Zan Lynx wrote:
> On Fri, 2007-12-07 at 15:22 -0800, Andrew Morton wrote:
>> On Fri, 07 Dec 2007 23:09:43 +0000
>> Zan Lynx <zlynx at acm.org> wrote:
>>> On Fri, 2007-12-07 at 15:02 -0800, Andrew Morton wrote:
>>>> On Fri, 07 Dec 2007 20:38:24 +0000
>>>> Zan Lynx <zlynx at acm.org> wrote:
>>>>> 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]
>> 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..

Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr at nospamshaw.ca
Home Page: http://www.roberthancock.com/

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