Alan wrote:
On Thu, 25 Jan 2007 20:29:47 +0900
Tejun Heo <[EMAIL PROTECTED]> wrote:
PIO xfermask limits should be shared by all devices on the same
channel to avoid violating device selection timing. libata used to
NAK, this is totally wrong
+ /* PIO xfermask limits are shared by all devices on the same
+ * channel to avoid violating device selection timing.
+ */
+ for (i = 0; i < ATA_MAX_DEVICES; i++) {
+ struct ata_device *d = &ap->device[i];
+ unsigned int pio_mask;
+
+ if (ata_dev_absent(d))
+ continue;
+
+ ata_unpack_xfermask(ata_id_xfermask(d->id),
+ &pio_mask, NULL, NULL);
+ pio_mask &= d->pio_mask;
+ xfer_mask &= ata_pack_xfermask(pio_mask, UINT_MAX, UINT_MAX);
+ }
NAK
This "guarantee" was deliberately removed long ago and is completely
bogus.
The good ATA chipsets do not suffer from selection timing limits of this
form. The less smart ones do and the drivers correctly merge the timing
Agreed.
I'm curious what the motivation of this patch was?
Jeff
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