Re: [MICROPATCH] Make x86_64 build work without GART_IOMMU

[Andrew Morton]

corbet@xxxxxxx (Jonathan Corbet) wrote:
>
> > > My Radeon 9200SE goes nuts if I build a GART-enabled
> > > kernel.  Haven't figured out why...
> > 
> > Define 'nuts' and supply full boot log (with GART enabled)
> 
> Oops, sorry for the technical term...:)

"No User Time Scheduled".  Silly Andi.

> Andrew asked for a profile to help track down where the kernel loop is.  I
> just did one, but the results are less than illuminating:
> 
> 	105219 total                                      0.0448
> 	 85232 __delay                                  2663.5000
> 	 14076 default_idle                             293.2500
> 	  4679 __do_softirq                              26.5852
> 	   474 check_poison_obj                           1.0216
> 	   197 handle_IRQ_event                           2.0521
> 	    91 kmem_cache_free                            0.1034

Yup, that's the one.  There are various loops where the driver spins on a
hardware register, with an mdelay() in the loop.

Can you get a sysrq-p trace?


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