[PATCH 1/1] ppc64: Block config accesses during BIST

Linas Vepstas linas at austin.ibm.com
Wed Sep 15 08:17:26 EST 2004


On Tue, Sep 14, 2004 at 11:19:18AM -0500, Brian King was heard to remark:
> Nathan Lynch wrote:
> >Is there a way to make an attempted config space read sleep until the
> >BIST is done?  E.g. the device's config space is protected by a
> >semaphore which must be held during accesses or during BIST.  Or is it
> >legal for the driver to access config space in interrupt context?
> 
> It is legal for the driver to access config space in interrupt context. 
> Additionally, the arch specific config space access routines get called 
> with a global spinlock held irqsave in the core pci code.

drivers/pci/access.c the lock is called "pci_lock", its declared static, 
and is thus appearently used *only* in this one file.  This lock doesn't 
seem to be protecting any data that I can obviously see.  My gut feel is
that this lock should be moved to the arch-specific code, where the
different arches could implement a global spinlock or something more
granular if they wish.

Anyone care to bring it up on LKML?  Maybe they'd go for it ... 

--linas



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