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

[Michael Elkins]

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