Signed-off-by: Alan Cox <alan@xxxxxxxxxx>
There are three flags being set by default by the PIIX driver for speeds
> PIO 1, and one not being cleared properly on fallback to PIO0. The
most important one is the prefetch/post write control which only works
for ATA and can do bad things with ATAPI.
The patch does its best to set the flags correctly for drivers/ide. Its
not 100% perfect but its closer than the original. 100% perfect requires
proper IORDY handling but this isn't critical (and its not right in
libata either .. yet)
Probably should live in -mm for a bit for testing
Alan
diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.17/drivers/ide/pci/piix.c linux-2.6.17/drivers/ide/pci/piix.c
--- linux.vanilla-2.6.17/drivers/ide/pci/piix.c 2006-06-19 17:17:24.000000000 +0100
+++ linux-2.6.17/drivers/ide/pci/piix.c 2006-06-26 13:44:49.296262720 +0100
@@ -222,29 +222,42 @@
unsigned long flags;
u16 master_data;
u8 slave_data;
+ int control = 0;
/* ISP RTC */
- u8 timings[][2] = { { 0, 0 },
- { 0, 0 },
- { 1, 0 },
- { 2, 1 },
- { 2, 3 }, };
+ static const u8 timings[][2]= {
+ { 0, 0 },
+ { 0, 0 },
+ { 1, 0 },
+ { 2, 1 },
+ { 2, 3 }, };
pio = ide_get_best_pio_mode(drive, pio, 5, NULL);
spin_lock_irqsave(&ide_lock, flags);
pci_read_config_word(dev, master_port, &master_data);
+
+ if (pio >= 2)
+ control |= 1; /* Programmable timing on */
+ if (drive->media == ide_disk)
+ control |= 4; /* Prefetch, post write */
+ if (pio >= 3)
+ control |= 2; /* IORDY */
if (is_slave) {
master_data = master_data | 0x4000;
- if (pio > 1)
+ if (pio > 1) {
/* enable PPE, IE and TIME */
- master_data = master_data | 0x0070;
+ master_data = master_data | (control << 4);
+ } else {
+ master_data &= ~0x0070;
+ }
pci_read_config_byte(dev, slave_port, &slave_data);
slave_data = slave_data & (hwif->channel ? 0x0f : 0xf0);
slave_data = slave_data | (((timings[pio][0] << 2) | timings[pio][1]) << (hwif->channel ? 4 : 0));
} else {
master_data = master_data & 0xccf8;
- if (pio > 1)
+ if (pio > 1) {
/* enable PPE, IE and TIME */
- master_data = master_data | 0x0007;
+ master_data = master_data | control;
+ }
master_data = master_data | (timings[pio][0] << 12) | (timings[pio][1] << 8);
}
pci_write_config_word(dev, master_port, master_data);
-
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