Re: [PATCH] Re: PROBLEM: kernel 2.4.0-test11-ac1 hang with usb-uhci and emu10k1

From: Michael Elkins (me@toesinperil.com)
Date: Fri Nov 24 2000 - 02:06:14 EST


On Thu, Nov 23, 2000 at 06:06:31PM -0500, Jeff Garzik wrote:
> Michael Elkins wrote:
> >
> > On Thu, Nov 23, 2000 at 05:49:52PM +0100, Georg Acher wrote:
> > It hangs in start_uhci():
> >
> > /* disable legacy emulation */
> > pci_write_config_word (dev, USBLEGSUP, USBLEGSUP_DEFAULT);
> >
> > The loop that the call is in gets iterated 5 times. For i < 4, the
> > if (!(dev->resource[i].flags & 1))
> > is TRUE, but on i==4, it drops into the bottom of the loop to execute
> > check_region() and then pci_write_config_word(), where it hangs.
>
> It may not make a difference, but that check is flat out wrong.

The loop still exhibits the same behavior.

/usr/include/linux/ioport.h:#define IORESOURCE_IO 0x00000100 /* Resource type */

Definitely a different value, however.

> Apply this patch... (untested, you may need to include ioport.h)

fyi, ioport.h isn't required.

On Thu, Nov 23, 2000 at 03:53:27PM -0800, Linus Torvalds wrote:
> Try changing the thing around a bit: make the above place say
>
> /* disable legacy emulation */
> pci_write_config_word (dev, USBLEGSUP, 0);
>
> and then AFTER we have successfully done a request_irq() call, we
> can enable PCI interrupts with
>
> /* Enable PIRQ */
> pci_write_config_word (dev, USBLEGSUP, USBLEGSUP_DEFAULT);
>
> Does that make it happier?

Yep! That seems to have fixed it. Added the pci_write_config_word() after
the request_irq() in alloc_uhci().

me
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