Re: [PATCH 1/5] ide: add short cables support

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Bartlomiej Zolnierkiewicz wrote:

> > > This patch allows users to override both host and device side cable detection
> > > with "ideX=ata66" kernel parameter.  Thanks to this it should be now possible
> > > to use UDMA > 2 modes on systems (laptops mainly) which use short 40-pin cable
> > > instead of 80-pin one.

> > > Next patches add automatic detection of some systems using short cables.

> > > Changes:

> > > * Rename hwif->udma_four to hwif->cbl and make it u8.

> >    Not sure if already short word "cable" was worth further shortening. :-)

> The name/usage is the same as in libata.

> When we add ->cable_detect method it will make grepping easier. 8)

   Hm... :-)

> > > Index: b/drivers/ide/pci/alim15x3.c
> > > ===================================================================
> > > --- a/drivers/ide/pci/alim15x3.c
> > > +++ b/drivers/ide/pci/alim15x3.c
> > > @@ -594,7 +594,7 @@ out:
> > >  *	FIXME: frobs bits that are not defined on newer ALi devicea
> > >  */
> > >
> > > -static unsigned int __devinit ata66_ali15x3 (ide_hwif_t *hwif)
> > > +static u8 __devinit ata66_ali15x3(ide_hwif_t *hwif)
> > > {
> > > 	struct pci_dev *dev	= hwif->pci_dev;
> > > 	unsigned int ata66	= 0;
> > > @@ -657,7 +657,7 @@ static unsigned int __devinit ata66_ali1
> > >
> > > 	local_irq_restore(flags);
> > >
> > > -	return(ata66);
> > > +	return ata66 ? ATA_CBL_PATA80 : ATA_CBL_PATA40;

> >    Ahem... I'd think it was about the right time to fix the abomination which
> > those ata66 and cable_80_pin[2] are, something like this:

> > static unsigned int __devinit ata66_ali15x3 (ide_hwif_t *hwif)
> > {
> >         struct pci_dev *dev     = hwif->pci_dev;
> >         unsigned int cbl        = ATA_CBL_PATA40;
> >         unsigned long flags;
> >         u8 tmpbyte, mask	= hwif->channel ? 0x02 : 0x01;
> >
> >         local_irq_save(flags); /* Not sure if it's necessary... */
> >
> >         if (m5229_revision >= 0xC2) {
> >                 /*
> >                  * Ultra66 cable detection (from Host View)
> >                  * m5229, 0x4a, bit0: primary, bit1: secondary
> > 		 * 0: 80 pin, 1: 40 pin
> >                  */
> >                 pci_read_config_byte(dev, 0x4a, &tmpbyte);
> >                 /*
> >                  * Allow ata66 if cable of current channel has 80 pins
> >                  */
> >                 cbl = (tmpbyte & mask) ? ATA_CBL_PATA40 : ATA_CBL_PATA80;
> >         } else {

> > [Following code frankly speaking has no business being in this function]

> patch #3/5 already takes care of cable_80_pin[2] part,

   I really should have looked thru all the series but lacked the time. :-<

> ata66 part was left as an exercise for the reader ;-)

   Hm, now that I've looked at that patch I saw both these things killed.
What, you don't know your own code? ;-)

> >         local_irq_restore(flags); /* Not sure if it's necessary... */

> > 	return cbl;

> > > }

> > > /**
> > > Index: b/drivers/ide/pci/serverworks.c
> > > ===================================================================
> > > --- a/drivers/ide/pci/serverworks.c
> > > +++ b/drivers/ide/pci/serverworks.c
> > > @@ -329,9 +329,9 @@ static unsigned int __devinit init_chips
> > > 	return dev->irq;
> > > }
> > >
> > > -static unsigned int __devinit ata66_svwks_svwks (ide_hwif_t *hwif)
> > > +static u8 __devinit ata66_svwks_svwks(ide_hwif_t *hwif)
> > > {
> > > -	return 1;
> > > +	return ATA_CBL_PATA80;
> > > }

> >    Hm, worth folding into ata66_svwks()...

> Yes and no...

> Alan did a very nice rewrite of cable detection code for pata_serverworks.c
> driver.  We may be better off just back-porting it (patches are welcomed).

   Thanks, no. I still have much to do. :-)

> > > Index: b/drivers/ide/pci/sis5513.c
> > > ===================================================================
> > > --- a/drivers/ide/pci/sis5513.c
> > > +++ b/drivers/ide/pci/sis5513.c
> > > @@ -796,7 +796,7 @@ static unsigned int __devinit init_chips
> > > 	return 0;
> > > }
> > >
> > > -static unsigned int __devinit ata66_sis5513 (ide_hwif_t *hwif)
> > > +static u8 __devinit ata66_sis5513(ide_hwif_t *hwif)
> > > {
> > > 	u8 ata66 = 0;
> > >
> > > @@ -811,7 +811,8 @@ static unsigned int __devinit ata66_sis5
> > > 		pci_read_config_byte(hwif->pci_dev, 0x48, &reg48h);
> > > 		ata66 = (reg48h & mask) ? 0 : 1;
> > > 	}
> > > -        return ata66;
> > > +
> > > +	return ata66 ? ATA_CBL_PATA80 : ATA_CBL_PATA40;
> > > }

> >    That doesn't look good as well. I think we should part with 'ata66' 
> > variable here completely...

> Could be fixed in the follow-up patch as we should also split ata66_sis5513()
> into two separate functions (one for chipset_family >= ATA_133 and one for
> chipset_family >= ATA_66).

   That's only worth doing if you actually intend to introduce cable_detect() 
method...

> Thanks,
> Bart

MBR, Sergei

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