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    SubjectRe: [PATCH 4/4] ata: pata_parport: fit3: implement IDE command set registers
    Date
    On Thursday 05 October 2023 21:53:44 Sergey Shtylyov wrote:
    > On 10/5/23 10:24 PM, Ondrej Zary wrote:
    >
    > > fit3 protocol driver does not support accessing IDE control registers
    > > (device control/altstatus). The DOS driver does not use these registers
    > > either (as observed from DOSEMU trace). But the HW seems to be capable
    > > of accessing these registers - I simply tried bit 3 and it works!
    > >
    > > The control register is required to properly reset ATAPI devices or
    > > they will be detected only once (after a power cycle).
    > >
    > > Tested with EXP Computer CD-865 with MC-1285B EPP cable and
    > > TransDisk 3000.
    > >
    > > Signed-off-by: Ondrej Zary <linux@zary.sk>
    >
    > Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
    >
    > > ---
    > > drivers/ata/pata_parport/fit3.c | 14 ++------------
    > > 1 file changed, 2 insertions(+), 12 deletions(-)
    > >
    > > diff --git a/drivers/ata/pata_parport/fit3.c b/drivers/ata/pata_parport/fit3.c
    > > index bad7aa920cdc..d2b81cf2e16d 100644
    > > --- a/drivers/ata/pata_parport/fit3.c
    > > +++ b/drivers/ata/pata_parport/fit3.c
    > [...]
    > > @@ -59,11 +53,7 @@ static int fit3_read_regr(struct pi_adapter *pi, int cont, int regr)
    > > {
    > > int a, b;
    > >
    > > - if (cont) {
    > > - if (regr != 6)
    > > - return 0xff;
    > > - regr = 7;
    > > - }
    > > + regr += cont << 3;
    >
    > So, is regr == 7 instead of 8 intentional?

    The original code read ATA_REG_STATUS (7) in context 0 instead of ALT_STATUS (6) in context 1.

    --
    Ondrej Zary

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