lkml.org 
[lkml]   [2008]   [Apr]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] x86, voyager: fix ioremap_nocache()
David Miller wrote:
> From: Jeff Garzik <jeff@garzik.org>
> Date: Sun, 27 Apr 2008 18:39:24 -0400
>
>> I disagree with this semantics change. A number of code places _and
>> drivers_ GET IT RIGHT, and these are all broken now?
>
> [ Note, James's patch that you quoted is about mapping DMA
> memory, in dma_declare_coherent_memory(), rather than devices.
> But I know what you are trying to talk about Jeff. :-) ]
>
> Wrt. ioremap() semanics, it is important to realize that if
> the implementation of this on x86 has been giving non-cached
> I/O mappings out up until recently, you can expect that there
> are hundreds of drivers that might now be broken.
>
> That's the sad fact of the ubiquity of x86, and it doesn't matter how
> we defined the API is some document.
>
> Anyways, my point is that this angle should be strongly considered in
> any discussion about ioremap() behavior.

Understood.

I guess I am more annoyed that this stealth semantics change appears to
have broken everything that depends on pci_iomap(), including 90%+ of
all libata drivers, unless I am missing something.

That one piece of code (pci_iomap) was correct under the old semantics,
on x86 and elsewhere. It's tested and working nicely, and depended upon
by many drivers.

Jeff





\
 
 \ /
  Last update: 2008-04-28 00:57    [W:0.101 / U:0.644 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site