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

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

Sergei Shtylyov wrote:
> Hello.

Hi,

> 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...

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

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

hehe

>> 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.

> 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.

>> 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... 

>> Index: b/drivers/ide/pci/pdc202xx_old.c
>> ===================================================================
>> --- a/drivers/ide/pci/pdc202xx_old.c
>> +++ b/drivers/ide/pci/pdc202xx_old.c
>> @@ -339,12 +339,10 @@ static int pdc202xx_config_drive_xfer_ra
>>       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))
>>               hwif->tuneproc(drive, 5);
> 
>    This driver's tuneproc() method always auto-tunes here instead of
> setting
> what it's told too -- I'll send a patch...

Please do...

>> Index: b/drivers/ide/pci/siimage.c
>> ===================================================================
>> --- a/drivers/ide/pci/siimage.c
>> +++ b/drivers/ide/pci/siimage.c
>> @@ -420,12 +420,10 @@ static int siimage_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 also always set PIO mode 4. More mess.

Yep, same bug as in cmd64x.c.

>> 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*...

Thanks,
Bart