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Subject[PATCH 6/15] atiixp/jmicron/triflex: fix PIO fallback
[PATCH] atiixp/jmicron/triflex: fix PIO fallback

* atiixp: if DMA can't be used atiixp_config_drive_for_dma() should return 0,
atiixp_dma_check() will tune the correct PIO mode anyway

* jmicron: if DMA can't be used config_chipset_for_dma() should return 0,
micron_config_drive_for_dma() will tune the correct PIO mode anyway

config_jmicron_chipset_for_pio(drive, !speed) doesn't program
device transfer mode for speed != 0 (only wastes some CPU cycles
on ide_get_best_pio_mode() call) so remove it

* triflex: if DMA can't be used triflex_config_drive_for_dma() should return 0,
triflex_config_drive_xfer_rate() will tune correct PIO mode anyway

Above changes also fix (theoretical) issue when ->speedproc fails to set
device transfer mode (i.e. when ide_config_drive_speed() fails to program it)
but one of DMA transfer modes is already enabled on the device by the BIOS.
In such scenario ide_dma_enable() will incorrectly return true statement
and ->ide_dma_check will try to enable DMA on the device.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

---
drivers/ide/pci/atiixp.c | 7 ++-----
drivers/ide/pci/jmicron.c | 4 +++-
drivers/ide/pci/triflex.c | 8 +++-----
3 files changed, 8 insertions(+), 11 deletions(-)
Index: b/drivers/ide/pci/atiixp.c
===================================================================
--- a/drivers/ide/pci/atiixp.c
+++ b/drivers/ide/pci/atiixp.c
@@ -235,11 +235,8 @@ static int atiixp_config_drive_for_dma(i
{
u8 speed = ide_dma_speed(drive, atiixp_ratemask(drive));

- /* If no DMA speed was available then disable DMA and use PIO. */
- if (!speed) {
- u8 tspeed = ide_get_best_pio_mode(drive, 255, 5, NULL);
- speed = atiixp_dma_2_pio(XFER_PIO_0 + tspeed) + XFER_PIO_0;
- }
+ if (!speed)
+ return 0;

(void) atiixp_speedproc(drive, speed);
return ide_dma_enable(drive);
Index: b/drivers/ide/pci/jmicron.c
===================================================================
--- a/drivers/ide/pci/jmicron.c
+++ b/drivers/ide/pci/jmicron.c
@@ -147,7 +147,9 @@ static int config_chipset_for_dma (ide_d
{
u8 speed = ide_dma_speed(drive, jmicron_ratemask(drive));

- config_jmicron_chipset_for_pio(drive, !speed);
+ if (!speed)
+ return 0;
+
jmicron_tune_chipset(drive, speed);
return ide_dma_enable(drive);
}
Index: b/drivers/ide/pci/triflex.c
===================================================================
--- a/drivers/ide/pci/triflex.c
+++ b/drivers/ide/pci/triflex.c
@@ -104,11 +104,9 @@ static int triflex_config_drive_for_dma(
{
int speed = ide_dma_speed(drive, 0); /* No ultra speeds */

- if (!speed) {
- u8 pspeed = ide_get_best_pio_mode(drive, 255, 4, NULL);
- speed = XFER_PIO_0 + pspeed;
- }
-
+ if (!speed)
+ return 0;
+
(void) triflex_tune_chipset(drive, speed);
return ide_dma_enable(drive);
}
-
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