Re: ehci-hcd on CARDBUS hangs when stopping card service

[Ingo Oeser]

On Sun, May 26, 2002 at 02:41:30PM +0100, David Woodhouse wrote:
> [e-mail] said:
> >  Also, it's generally a good idea to "just say no" to endless loops in
> > drivers. Hardware bugs _do_ happen, and it's a lot more pleasant to
> > have the driver do a
> > 	printk("Device does not respond\n");
> > than for the kernel to hang.
> 
> Too late. On some hardware, if you try to talk to the device once it's 
> gone, you're already dead. Not all the world is a PeeCee.

That happens even on a "PeeCee". 

Situation: 
   - Normal readl() of a ioremap()ed register set of a
     PCI device[1]:
   -> machine hangs hard (no magic sysrq possible, no Ooops, no
      panic printed) 
      
   - Several DWORD reads of the same register set succeded before
     and the register is wired according to the SPEC.

Just to provide an argument here

PS: I wish I had an PCI Analyzer available...

[1] TI TMS320C6x EVM Board[2], Rev. 3 
   with PCI-Bridge Chip AMCC S5933[3] hanging the host side on Busmaster DMA.

[2] PCI-ID: 0x104c:0x1002
[3] PCI-ID: 0x10e8:0x4750 or 0x10e8:0x807d or 0x10e8:0x809c
-- 
Science is what we can tell a computer. Art is everything else. --- D.E.Knuth