Hi,
On Monday 12 November 2007, Andrew Morton wrote:
> On Fri, 09 Nov 2007 11:22:41 +0100 Jonas Stare <[EMAIL PROTECTED]> wrote:
>
> > Hi.
> >
> > This week I ran into a strange hardware problem. During boot I got a 35
> > second delay while waiting for IDE-disks that weren't there to report
With what chipset and host driver does this happen?
> > that they were not in a BSY state. The problem was most likely in the
> > hardware but this patch enables you to ignore waiting for disks by
> > setting hdX=noprobe (and not setting the geometry by hand) as a kernel
> > option.
> >
> > If no noprobe-option is set the code will work (more or less) as the
> > original but if set the code will skip the ide_wait_not_busy() for that
> > drive. Even if there would be a drive there and it is still BSY
> > afterwards it should not matter since it isn't probed for later.
> >
> > There are other ways to get around the "35-seconds-of-waiting-in-vain",
> > like actually fix the hardware, insert a second drive that works or
> > recompile the kernel with edd-support builtin (atleast I've seen that
> > solution on a forum) and possibly others. But this patch would allow
> > people to get Linux to boot quickly on wonky hardware without having to
> > recompile anything.
>
> > (The code also honors the MAX_DRIVES variable instead of assuming that
> > ther will be 2 drives on the bus.)
>
> I keep on hearing about problems with boot-time IDE probing. It's public
> enemy #1 with the embedded guys.
The problem is that we are not hearing about them.
Please forward the reports to [EMAIL PROTECTED]
> It does seem that operator intervention is needed in some fashion.
>
> > I will be happy for all the comments I can get. :) But be gentle, this
> > is my first patch...
Jonas, could you also put printk() dumping content of 'stat' in
ide-iops.c::ide_wait_not_busy() so we can verify that it is not
some problem with ide_wait_not_busy() itself.
> > Best regards
> > Jonas Stare
> >
> > Signed-off-by: Jonas Stare <[EMAIL PROTECTED]>
> > --
> > diff -u linux-2.6.23.1-orig/drivers/ide/ide-probe.c
> > linux-2.6.23.1/drivers/ide/ide-probe.c
> > --- linux-2.6.23.1-orig/drivers/ide/ide-probe.c 2007-10-12
> > 18:43:44.000000000 +0200
> > +++ linux-2.6.23.1/drivers/ide/ide-probe.c 2007-11-09
> > 10:43:16.000000000 +0100
> > @@ -643,6 +643,7 @@
> > static int wait_hwif_ready(ide_hwif_t *hwif)
> > {
> > int rc;
> > + int unit;
> >
> > printk(KERN_DEBUG "Probing IDE interface %s...\n", hwif->name);
> >
> > @@ -659,20 +660,24 @@
> > return rc;
> >
Hmm, so the first ide_wait_not_busy() (for the currently
selected device) is OK and doesn't stall?
> > /* Now make sure both master & slave are ready */
> > - SELECT_DRIVE(&hwif->drives[0]);
> > - hwif->OUTB(8, hwif->io_ports[IDE_CONTROL_OFFSET]);
> > - mdelay(2);
> > - rc = ide_wait_not_busy(hwif, 35000);
> > - if (rc)
> > - return rc;
> > - SELECT_DRIVE(&hwif->drives[1]);
> > - hwif->OUTB(8, hwif->io_ports[IDE_CONTROL_OFFSET]);
> > - mdelay(2);
> > - rc = ide_wait_not_busy(hwif, 35000);
> > + for (unit = 0; unit < MAX_DRIVES; ++unit) {
> > + /* Ignore disks that we will not probe for later. */
> > + if (!hwif->drives[unit].noprobe ||
> > + hwif->drives[unit].forced_geom) {
It is better to check for ->present
(->forced_geom implies that ->present is set).
> > + SELECT_DRIVE(&hwif->drives[unit]);
> > + hwif->OUTB(8, hwif->io_ports[IDE_CONTROL_OFFSET]);
> > + mdelay(2);
> > + rc = ide_wait_not_busy(hwif, 35000);
> > + /* Exit function with master selected (let's be
> > sane) */
> > + SELECT_DRIVE(&hwif->drives[0]);
This changes the previous behavior adding an extra SELECT_DRIVE()
before trying the slave drive.
> > + if (rc)
> > + return rc;
> > + } else {
> > + printk(KERN_DEBUG "Skip ide_wait_not_busy for
> > %s:%d\n",
> > + hwif->name, unit);
> > + }
> > + }
> >
> > - /* Exit function with master reselected (let's be sane) */
> > - SELECT_DRIVE(&hwif->drives[0]);
> > -
> > return rc;
> > }
>
> Maybe that's the fix, maybe not - I'll defer to others on that (please).
>
> Your email client is wordwrapping the text, and replaces tabs with spaces.
> Most of them seem to do this nowadays. For thunderbird, please see
> http://mbligh.org/linuxdocs/Email/Clients/Thunderbird
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