Re: [PATCH 8/15] ide: disable DMA in ->ide_dma_check for "no IORDY" case

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Hello.

Bartlomiej Zolnierkiewicz wrote:

[PATCH] ide: disable DMA in ->ide_dma_check for "no IORDY" case

  I've looked thru the code, and found more issues with the PIO fallback
there. Will try to cook up patches for at least some drivers...

Great, if possible please base them on top of the IDE tree...

Erm, I had doubts about it (having in mind that all that code is more of a cleanups than fixes). Maybe it'd be a good idea to separate the fix and cleanup series somehow...

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>

Index: b/drivers/ide/pci/aec62xx.c
===================================================================
--- a/drivers/ide/pci/aec62xx.c
+++ b/drivers/ide/pci/aec62xx.c
@@ -214,12 +214,10 @@ static int aec62xx_config_drive_xfer_rat
     if (ide_use_dma(drive) && config_chipset_for_dma(drive))
             return hwif->ide_dma_on(drive);

-     if (ide_use_fast_pio(drive)) {
+     if (ide_use_fast_pio(drive))
             aec62xx_tune_drive(drive, 5);

  This function looks like it's working (thouugh having the wrong limit of
PIO5 on auto-tuning) but is unnecassary complex.

Yes, it seems that there are actually two bugs here:
* the maximum allowed PIO mode should be PIO4 not PIO5
* for auto-tuning ("pio" == 255) it incorrectly sets PIO0
  (255 fails to the default case in the switch statement)

Yeah, you if you pass 255, it won't work (so, drive->autotune must be broken). But the driver itself have the wrong idea of 5 meaning auto-tune, so fallback should still work.

  Heh, the driver is certainly a rip-off form hpt366.c. What a doubtful
example they have chosen... :-)

hehe

   The driver's authorship explains it all. :-)

Index: b/drivers/ide/pci/atiixp.c
===================================================================
--- a/drivers/ide/pci/atiixp.c
+++ b/drivers/ide/pci/atiixp.c
@@ -264,10 +264,9 @@ static int atiixp_dma_check(ide_drive_t
             tspeed = ide_get_best_pio_mode(drive, 255, 5, NULL);
             speed = atiixp_dma_2_pio(XFER_PIO_0 + tspeed) + XFER_PIO_0;

  It's simply stupid to convert PIO mode to PIO mode. The whole idea is
doubtful as well..

It is side-effect of basing atiixp on piix driver.  Fixing it will allow PIO1
to be used (good) because atiixp_dma_2_pio() always downgrades PIO1 to PIO0
(leftover from piix - on Intel chipsets same timings are used for PIO0/1).

             hwif->speedproc(drive, speed);

  Well, well, the tuneproc() method can't ahndle auto-tunuing here
(255)...

Yes, definitely a bug.

Ugh... don't expect patches form me soon though. My first priority is the drivers that we support here...

And it also doesn't set up drive's own speed. The code seem to be another
rip-off from piix.c, repeating all its mistakes... :-)

:)

Index: b/drivers/ide/pci/cmd64x.c
===================================================================
--- a/drivers/ide/pci/cmd64x.c
+++ b/drivers/ide/pci/cmd64x.c
@@ -479,12 +479,10 @@ static int cmd64x_config_drive_for_dma (
     if (ide_use_dma(drive) && config_chipset_for_dma(drive))
             return hwif->ide_dma_on(drive);

-     if (ide_use_fast_pio(drive)) {
+     if (ide_use_fast_pio(drive))
             config_chipset_for_pio(drive, 1);

  This function will always set PIO mode 4. Mess.

Yep.

   I'm going to send the patch for both this and siimage.c...

Index: b/drivers/ide/pci/cs5535.c
===================================================================
--- a/drivers/ide/pci/cs5535.c
+++ b/drivers/ide/pci/cs5535.c
@@ -206,10 +206,9 @@ static int cs5535_dma_check(ide_drive_t
     if (ide_use_fast_pio(drive)) {
             speed = ide_get_best_pio_mode(drive, 255, 4, NULL);
             cs5535_set_drive(drive, speed);

  Could be folded into tuneproc() method call.

Using ->tuneproc() will also set the PIO mode on the drive
which is not done currently...

Hm, ide_config_drive_speed() is called by both tuneproc() method and cs5535_set_drive(), so I saw no issue there...

Index: b/drivers/ide/pci/sis5513.c
===================================================================
--- a/drivers/ide/pci/sis5513.c
+++ b/drivers/ide/pci/sis5513.c
@@ -678,12 +678,10 @@ static int sis5513_config_xfer_rate(ide_
     if (ide_use_dma(drive) && config_chipset_for_dma(drive))
             return hwif->ide_dma_on(drive);

-     if (ide_use_fast_pio(drive)) {
+     if (ide_use_fast_pio(drive))
             sis5513_tune_drive(drive, 5);

   Ugh, PIO fallback effectively always tries to set mode 4 here (thanks
it's not 5). Mess.

Yep, but it seems to be even more complicated since config_art_rwp_pio()
is a mess^2 - chipset is programmed to the best PIO mode while the
device is set to PIO4... *sigh*...

   Sorry, this one is low prio for me... :-)

Thanks,
Bart

MBR, Sergei
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