Hello.
Alan wrote:
Alan/Bart/anybody, could you enlighten me why hwif->rw_disk() method came
into being at all?
When you needed to wrap entire disk operations. The ->dma_ methods only
wrap DMA commands.
BTW, I've looked at the clock turnaround code both in drivers/ide/hpt366.c
and drivers/ata/pata_hpt3x2n.c and compared it to the HighPoint driver and I'm
dazed and confused (again?): contrary to what HighPoint does (I'm not sure
they're still doing it at all due to confused nature of their drivers :-),
Linux uses DPLL on reads and PCI clock on writes. The libata driver seem to
have an explicit contradiction:
static int hpt3x2n_use_dpll(struct ata_port *ap, int reading)
{
long flags = (long)ap->host->private_data;
/* See if we should use the DPLL */
if (reading == 0)
return USE_DPLL; /* Needed for write */
if (flags & PCI66)
return USE_DPLL; /* Needed at 66Mhz */
return 0;
}
static unsigned int hpt3x2n_qc_issue_prot(struct ata_queued_cmd *qc)
{
struct ata_taskfile *tf = &qc->tf;
struct ata_port *ap = qc->ap;
int flags = (long)ap->host->private_data;
if (hpt3x2n_pair_idle(ap)) {
int dpll = hpt3x2n_use_dpll(ap, (tf->flags & ATA_TFLAG_WRITE));
if ((flags & USE_DPLL) != dpll) {
if (dpll == 1)
hpt3x2n_set_clock(ap, 0x21);
else
hpt3x2n_set_clock(ap, 0x23);
}
}
return ata_qc_issue_prot(qc);
}
ATA_TFLAG_WRITE indicates a write transfer (host-to-device) while
hpt3x2n_use_dpll() contrarywise expects the read transfer indication. Comments?
WBR, Sergei
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