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SubjectRe: [PATCH] drivers/ide/ide-probe.c, kernel 2.6.23.1
On Fri, 09 Nov 2007 11:22:41 +0100 Jonas Stare <jonas.stare@purplescout.se> 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
> 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.

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...
>
> Best regards
> Jonas Stare
>
> Signed-off-by: Jonas Stare <jonas.stare@purplescout.se>
> --
> 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;
>
> /* 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) {
> + 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]);
> + 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).

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