To: misc@openbsd.org
Subject: fu: wdc_pcmcia and ATA mode
I wrote:
> I'm to install OpenBSD on an old Thinkpad, but I first need to dump
> the curr hdd contents, using the install cd, to a large CF card, via
> a PCMCIA adapter.
>
> The pcmcia stuff is correctly detected by the kernel, but wdc_pcmcia
> only appears to access the device in pcmcia mode (1-sector PIO),
> killing performance. I'm sure the CF card supports ATA mode and DMA
> as it's been used in the past as an ATA device through (guess what)
> an appropriate adapter.
Okay, I got a little further with this, but it didn't resolve the issue.
The adapter is a TS0MCF2PC. I haven't been able to open it up (glue is
involved and I simply don't have a thin enough screwdriver or knife to
avoid breaking the plastic). The flash card I used during the above is
an old SanDisk SDCFB 256M; it was for testing, only. Yesterday the card I
actually intend to use arrived, a Transcend TS64GCF400.
However, even that card, which is specified to support 'UDMA7', is used
by OpenBSD in what NetBSD (I tried it just in case) appears to call 'i/o
mapped mode'. 'memory mapped mode' appears to be an option on the other
side of the fence (or bikeshed?) there, but the straightforward route
would IMO still be to treat the card as an ATA device.
This leaves me with two concrete questions:
1) Does the cbb actually allow the card to work in ATA mode?
2) If so, why does OpenBSD not support it?
Perhaps, with help (I find modern kernels *slightly* overcomplicated, so
I'm bound to get some things wrong), I can then provide a patch to at
least work around this issue.
dmesg output will be provided later today (not via the 10-finger
interface <g>).
--schaafuit.
