Re: [PATCH 3/6] ide-pmac: PIO fixes

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Bartlomiej Zolnierkiewicz wrote:

> * Add { 0, 0 } entry to {kauai,shasta}_pio_timings[] so kauai_lookup_timing()
>   always returns a valid PIO timing (fixes PIO timing not being set for devices
>   with minimum PIO cycle <= 120ns).

    Ugh... the way those tables are following each other, the driver should be 
programming MWDMA2 timings instead. :-/

> * Add setting transfer mode on the device to pmac_ide_set_pio_mode().

> * Fix pmac_ide_set_pio() to always program chipset for given PIO timing instead
>   of only when the device we want to program PIO timing for is the currently
>   selected one.

    Hm, why this was necessary?
    AFAIU, pmac_ide_do_setfeature() will cause selectproc() to be called 
anyway, via SELECT_DRIVE()...

> * Now that pmac_ide_set_pio() is fixed there is no need to set transfer mode
>   on the device and program chipset for PIO in pmac_ide_tune_chipset()

    BTW, I'm also not seeing much sense in calling 
pmac_ide_do_update_timings() from there as well since pmac_ide_do_setfeature() 
is called before that anyway.

>   (returning 0 == success is not entirely correct but is OK for now since
>   the upper layers are only checking ->speedproc return value for DMA modes).

> This patch should have no effect on the default kernel behavior because
> IDE pmac driver doesn't enable ->autotune (this would also explain why some
> of the above bugs remained unfixed for so long).

> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>

MBR, Sergei