IDE cable detection on Apple PowerBook

[TOMARI Hisanobu]

Thanks for helpful advices.
This patch adds an option to drivers/ide/Kconfig and adds 
some lines to drivers/ide/pmac.c . Now the driver checks
if the model is prefixed with "PowerBook" and the entire hack
can be toggled in the Kconfig.

Again, the patch is against linux 2.6.28.8.

Best regards,
TOMARI Hisanobu

p.s. oddly, the drive works in ATA/100 mode under untouched
MacOS X 10.5.

On Thu, 19 Mar 2009 17:08:37 +1100
Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:

> On Thu, 2009-03-19 at 17:07 +1100, Benjamin Herrenschmidt wrote:
> > On Wed, 2009-03-18 at 22:47 +0900, TOMARI Hisanobu wrote:
> > > I thought the short-40pin assumption would cause no problem
> > > considering all models beginning with "PowerBook5" are laptops.
> > > Do you mean an option to toggle this hack on/off should be present 
> > > in Kconfig?
> > 
> > Actually, it makes -some- amount of sense to do it by testing
> > specifically for the prefix "PowerBook" and "iBook" without a specific
> > number I suppose.
> 
> Actually "PowerBook" is enough, there's no iBook prefix in the
> device-tree, I was confusing with old busted iMac firmwares that used
> iMac instead of PowerMac in there.
> 
> Cheers,
> Ben.
> 
> > Ben.
> > 
> > > Thanks,
> > > TOMARI Hisanobu
> > > 
> > > On Wed, 18 Mar 2009 18:58:17 +1100
> > > Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:
> > > 
> > > > On Wed, 2009-03-18 at 14:06 +0900, TOMARI Hisanobu wrote:
> > > > > Hello,
> > > > > 
> > > > > I'm using an OCZ PATA SSD on Apple PowerBook5,4 computer.
> > > > > The IDE drive fails to recognize 80-conductor cable that
> > > > > connects the drive to motherboard to fall back to UDMA33.
> > > > > 
> > > > > This patch fixes this behavior by assuming that the cable is
> > > > > short-40pin when the model string matches "PowerBook5" and 
> > > > > the motherboard detects 80c cable.
> > > > > 
> > > > > This patch is against drivers/ide/pmac.c in linux 2.6.28.8.
> > > > 
> > > > The patch is too much of an ad-hoc hack... _maybe_ an option is to make
> > > > the core fallback to 40 "short" when 80 pin detection fails on
> > > > powerbooks instead ?
> > > > 
> > > > Ben.
> > > > 
> > > > > (before applying the patch) hdparm -i /dev/hda
> > > > > /dev/hda:
> > > > >  Timing buffered disk reads:   90 MB in  3.03 seconds =  29.73 MB/sec
> > > > > (dmesg 2.6.26)
> > > > > ide0: Found Apple UniNorth ATA-6 controller, bus ID 3, irq 39
> > > > > Probing IDE interface ide0...
> > > > > hda: CORE_PATA, ATA DISK drive
> > > > > hda: host max PIO4 wanted PIO255(auto-tune) selected PIO4
> > > > > hda: drive side 80-wire cable detection failed, limiting max speed to UDMA33
> > > > > hda: UDMA/33 mode selected
> > > > > 
> > > > > (after applying the patch) hdparm -i /dev/hda
> > > > > /dev/hda:
> > > > >  Timing buffered disk reads:  240 MB in  3.02 seconds =  79.42 MB/sec
> > > > > (dmesg 2.6.28.8)
> > > > > ide-pmac: Found Apple UniNorth ATA-6 controller (PCI), bus ID 3, irq 39
> > > > > Probing IDE interface ide0...
> > > > > hda: CORE_PATA, ATA DISK drive
> > > > > hda: host max PIO4 wanted PIO255(auto-tune) selected PIO4
> > > > > hda: UDMA/100 mode selected
> > > > > ide0 at 0xf102a000-0xf102a070,0xf102a160 on irq 39
> > > > > 
> > > > > 
> > > > > _______________________________________________
> > > > > Linuxppc-dev mailing list
> > > > > Linuxppc-dev at ozlabs.org
> > > > > https://ozlabs.org/mailman/listinfo/linuxppc-dev
> > > > 
> 
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