Re: Reverting old hack

[Yoichi Yuasa <yuasa@linux-mips.org>]

On Wed, 24 Feb 2010 17:41:00 +0100
Ralf Baechle <ralf@linux-mips.org> wrote:

> On Wed, Feb 24, 2010 at 09:03:33AM +0900, Yoichi Yuasa wrote:
> 
> > > approach Ben suggested long ago:
> > >     http://marc.info/?l=linux-kernel&m=119733290624544&w=2
> > 
> > It works fine with 2.6.34 queue tree.
> > pci.c change is already committed by Ralf.
> 
> Which I just dropped from queue.  To keep the tree bisectable removal of
> the old hack and adding the fixup should be done in the same patch so I'd
> go for Bjorn's patch.
> 
> There is another somewhat theoretical correctness issue.  Because the
> VIA SuperIO chip only decodes 24 bits of address space but port address
> space currently being configured as 32MB there is the theoretical
> possibility of I/O port addresses that alias with legacy addresses getting
> allocated.
> 
> The complicated solution is to reserve all address range that potencially
> could cause such aliases.  But with the PCI spec limiting port allocations
> for devices to a maximum of 256 bytes 16MB of port address space already is
> way more than one would ever expect to be used so I suggest to just limit
> the port address space to 16MB.
> 
> Could you test the patch below?

It has no problem.

$ cat /proc/ioports                                                      
00000000-0000001f : reserved                                                    
00000020-00000021 : pic1                                                        
00000060-0000006f : reserved                                                    
00000070-00000077 : rtc_cmos                                                    
  00000070-00000077 : rtc0                                                      
00000080-0000008f : reserved                                                    
000000a0-000000a1 : pic2                                                        
000000c0-000000df : reserved                                                    
00000170-00000177 : pata_via                                                    
000001f0-000001f7 : pata_via                                                    
00000376-00000376 : pata_via                                                    
000003f6-000003f6 : pata_via                                                    
00001000-00ffffff : PCI I/O                                                     
  00001000-0000107f : 0000:00:07.0                                              
    00001000-0000107f : tulip                                                   
  00001080-000010ff : 0000:00:0c.0                                              
    00001080-000010ff : tulip                                                   
  00001400-0000141f : 0000:00:09.2                                              
  00001420-0000142f : 0000:00:09.1                                              
    00001420-0000142f : pata_via

Yoichi