Re: x86: Increase PCIBIOS_MIN_IO to 0x1500 to fix nForce 4 suspend-to-RAM

[Rafael J. Wysocki]

On Sunday, 23 of December 2007, Carlos Corbacho wrote:
> Fix suspend-to-RAM on nForce 4 (CK804) boards by increasing
> PCIBIOS_MIN_IO.
> 
> Fixes kernel bugzilla #9528
> 
> Problem:
> 
> Linus' patch (52ade9b3b97fd3bea42842a056fe0786c28d0555) to re-order
> suspend (and fix fall out from Rafael's earlier suspend reordering work)
> broke suspend-to-RAM on nForce 4 (CK804) boards.
> 
> Why:
> 
> After debugging _PTS() in the DSDT, it turns out these nVidia boards are
> trying to write to an IO port > 0x1000 (0x142E) during suspend. Before the
> re-ordering, we got away with this.
> 
> After the afore mentioned commit, we started hitting the PCIBIOS_MIN_IO
> limit and suspend then broke on these machines (the machine simply hangs
> when it reaches the 0x142E IO port write during suspend-to-RAM).
> 
> There was some previous work in the PCIBIOS_MIN_IO area over two years ago
> (71db63acff69618b3d9d3114bd061938150e146b) which bumped this to 0x4000,
> but this was reverted (2ba84684e8cf6f980e4e95a2300f53a505eb794e) after
> causing new and entirely different problems on another nForce board.
> 
> 0x1500 has been picked here as a nice, round and more conservative value
> than 0x4000, and which covers 0x142E.

The patch is fine by me, so if anyone has objections, please speak up.

Thanks,
Rafael


> Tested on x86-64.
> 
> Signed-off-by: Carlos Corbacho <carlos@xxxxxxxxxxxxxxxxxxx>
> CC: Rafael J. Wysocki <rjw@xxxxxxx>
> CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> CC: Greg KH <gregkh@xxxxxxx>
> CC: Ingo Molnar <mingo@xxxxxxx>
> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> CC: Len Brown <lenb@xxxxxxxxxx>
> ---
> Since it's not entirely clear who is responsible for what in this file,
> and given what it fixes, I'm CC'ing you all in the hope that someone
> will handle this.
> 
>  include/asm-x86/pci.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> 
> diff --git a/include/asm-x86/pci.h b/include/asm-x86/pci.h
> index e883619..03cb123 100644
> --- a/include/asm-x86/pci.h
> +++ b/include/asm-x86/pci.h
> @@ -46,7 +46,7 @@ extern unsigned int pcibios_assign_all_busses(void);
>  #define pcibios_scan_all_fns(a, b)	0
>  
>  extern unsigned long pci_mem_start;
> -#define PCIBIOS_MIN_IO		0x1000
> +#define PCIBIOS_MIN_IO		0x1500
>  #define PCIBIOS_MIN_MEM		(pci_mem_start)
>  
>  #define PCIBIOS_MIN_CARDBUS_IO	0x4000
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