Re: [RFC] disable PCIE 'Enable No Snoop' bit by default

2007-09-10 Thread Shaohua Li
On Mon, 2007-09-10 at 23:15 -0700, Greg KH wrote: > On Tue, Sep 11, 2007 at 09:29:43AM +0800, Shaohua Li wrote: > > On Sun, 2007-09-09 at 09:43 -0700, Greg KH wrote: > > > On Thu, Sep 06, 2007 at 05:40:38AM -0700, David Miller wrote: > > > > From: Matthew Wilcox <[EMAIL PROTECTED]> > > > > Date: Th

Re: [RFC] disable PCIE 'Enable No Snoop' bit by default

2007-09-10 Thread Greg KH
On Tue, Sep 11, 2007 at 09:29:43AM +0800, Shaohua Li wrote: > On Sun, 2007-09-09 at 09:43 -0700, Greg KH wrote: > > On Thu, Sep 06, 2007 at 05:40:38AM -0700, David Miller wrote: > > > From: Matthew Wilcox <[EMAIL PROTECTED]> > > > Date: Thu, 6 Sep 2007 05:57:31 -0600 > > > > > > > I'm not sure you

Re: [RFC] disable PCIE 'Enable No Snoop' bit by default

2007-09-10 Thread Shaohua Li
On Sun, 2007-09-09 at 09:43 -0700, Greg KH wrote: > On Thu, Sep 06, 2007 at 05:40:38AM -0700, David Miller wrote: > > From: Matthew Wilcox <[EMAIL PROTECTED]> > > Date: Thu, 6 Sep 2007 05:57:31 -0600 > > > > > I'm not sure your analysis is correct. Here's what my draft copy of > > > the pcie 2.0

Re: [RFC] disable PCIE 'Enable No Snoop' bit by default

2007-09-09 Thread Greg KH
On Thu, Sep 06, 2007 at 05:40:38AM -0700, David Miller wrote: > From: Matthew Wilcox <[EMAIL PROTECTED]> > Date: Thu, 6 Sep 2007 05:57:31 -0600 > > > I'm not sure your analysis is correct. Here's what my draft copy of > > the pcie 2.0 spec says: > > > > Enble No Snoop ? If this bit is Set, the

Re: [RFC] disable PCIE 'Enable No Snoop' bit by default

2007-09-06 Thread Shaohua Li
On Thu, 2007-09-06 at 05:57 -0600, Matthew Wilcox wrote: > On Thu, Sep 06, 2007 at 01:35:08PM +0800, Shaohua Li wrote: > > PCIE 'Enable No Snoop' bit is set by default per PCIE spec, but OS > > assumes PCI DMA is snooped, which is legacy PCI device does. Enabling no > > snoop might cause potential

Re: [RFC] disable PCIE 'Enable No Snoop' bit by default

2007-09-06 Thread David Miller
From: Matthew Wilcox <[EMAIL PROTECTED]> Date: Thu, 6 Sep 2007 05:57:31 -0600 > I'm not sure your analysis is correct. Here's what my draft copy of > the pcie 2.0 spec says: > > Enble No Snoop ­ If this bit is Set, the Function is permitted to > Set the No Snoop bit in the Requester Attribut

Re: [RFC] disable PCIE 'Enable No Snoop' bit by default

2007-09-06 Thread Matthew Wilcox
On Thu, Sep 06, 2007 at 01:35:08PM +0800, Shaohua Li wrote: > PCIE 'Enable No Snoop' bit is set by default per PCIE spec, but OS > assumes PCI DMA is snooped, which is legacy PCI device does. Enabling no > snoop might cause potential DMA issues. This patch disables it, if a > driver can work with n

[RFC] disable PCIE 'Enable No Snoop' bit by default

2007-09-05 Thread Shaohua Li
PCIE 'Enable No Snoop' bit is set by default per PCIE spec, but OS assumes PCI DMA is snooped, which is legacy PCI device does. Enabling no snoop might cause potential DMA issues. This patch disables it, if a driver can work with no snoop, we can provide a helper to enable it. I didn't see any rea