Messages in this thread | | | Date | Fri, 24 Jan 2003 15:46:35 -0500 | From | "Wiedemeier, Jeff" <> | Subject | Re: [patch 2.5] tg3.c: pci_{save,restore}_extended_state |
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On Fri, Jan 24, 2003 at 03:34:02PM -0500, Jeff Garzik wrote: > On Fri, Jan 24, 2003 at 03:24:53PM -0500, Wiedemeier, Jeff wrote: > > On Fri, Jan 24, 2003 at 03:05:38PM -0500, Jeff Garzik wrote: > > If the intent is to just not use MSI on tg3 devices, I can use the pci > > quirks to make sure that MSI gets turned off for tg3 devices. > > hmmm, maybe I am missing something?
Quoting section 6.8.1.3 of the PCI 2.2 spec (talking about message control in PCI config space):
This register provides system software control over MSI. After reset, MSI is disabled (bit 0 is cleared) and the function requests servicing via its INTx# pin (if supported). System sofware can enable MSI by setting bit 0 of this register. System software is permitted to modify the Message Control register's read/write bits and fields. A device driver is not permitted to modify the Message Control register's read/write bits and fields.
> AFAICS, this is a per-driver decision, and needs to be done at the > driver level, in the tg3 driver source.
The last sentence in the quote above indicates that it is not intended (by the PCI spec) to be a per-driver decision, but rather a system decision. The messages used are also a per-bus system resource and how an MSI goes from the PCI bus to the rest of the system (i.e. the CPU(s)) is implementation dependent.
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