Re: [RFC PATCH] libata-sff: Fix oops reported in kerneloops.org forpnp devices with no ctl

[Jeff Garzik]

Alan Cox wrote:
> > > Want me to roll a patch in that style ?
> > Works for me...
>
> Ok
>
> - Make ata_sff_altstatus private so nobody uses it by mistake
> - Drop the 400nS delay from it
>
> Add
>
> ata_sff_irq_status	-	encapsulates the IRQ check logic
>
> This function keeps the existing behaviour for altstatus using devices. I
> actually suspect the logic was wrong before the changes but -rc isn't the
> time to play with that
>
> ata_sff_sync		-	ensure writes hit the device
>
> Really we want an io* operation for 'is posted' eg ioisposted(ioaddr) so
> that we can fix the nasty delay this causes on most systems.
>
> - ata_sff_pause		-	400nS delay
>
> Ensure the command hit the device and delay 400nS
>
> - ata_sff_dma_pause
>
> Ensure the I/O hit the device and enforce an HDMA1:0 transition delay.
> Requires altstatus register exists, BUG if not so we don't risk
> corruption in MWDMA modes. (UDMA the checksum will save your backside in
> theory)
>
> The only other complication then is devices with their own handlers.
> rb532 can use dma_pause but scc needs to access its own altstatus
> register for internal errata workarounds so directly call the drivers own
> altstatus function.
>
>
> Signed-off-by: Alan Cox <alan@xxxxxxxxxx>
>
>  drivers/ata/libata-sff.c    |  115 +++++++++++++++++++++++++++++++++++++------
>  drivers/ata/pata_icside.c   |    2 -
>  drivers/ata/pata_rb532_cf.c |    4 +
>  drivers/ata/pata_scc.c      |    5 +-
>  include/linux/libata.h      |   16 +-----
>  5 files changed, 109 insertions(+), 33 deletions(-)

ACK

If no further comments, I'm OK with this version...


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