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Message-ID: <45B117D4.7050406@gmail.com>
Date: Fri, 19 Jan 2007 20:11:16 +0100
From: Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
To: Sergei Shtylyov <sshtylyov@...mvista.com>
CC: linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 8/15] ide: disable DMA in ->ide_dma_check for "no IORDY"
case
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@...il.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
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