linux-kernel - Re: [PATCH 8/15] ide: disable DMA in ->ide_dma

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Message-ID: <45B0F12B.3000202@ru.mvista.com>
Date:	Fri, 19 Jan 2007 19:26:19 +0300
From:	Sergei Shtylyov <sshtylyov@...mvista.com>
To:	Bartlomiej Zolnierkiewicz <bzolnier@...il.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

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...

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

> 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..

>  		hwif->speedproc(drive, speed);

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

> 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.

> 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...

> 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.

> 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.

MBR, Sergei
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