On Tue, 2009-03-17 at 08:54 -0400, Matthew Wilcox wrote:
> I didn't find the previous version very useful, so I rewrote it.
>
> Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
> Reviewed-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
> Reviewed-by: Grant Grundler <grundler@xxxxxxxxxxxxxxxxx>
Sorry I didn't comment on this previously, but it occured to me the
other day ..
> ---
> Documentation/PCI/MSI-HOWTO.txt | 758 ++++++++++++++-------------------------
> 1 files changed, 277 insertions(+), 481 deletions(-)
>
> diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt
> index 256defd..1c02431 100644
> --- a/Documentation/PCI/MSI-HOWTO.txt
> +++ b/Documentation/PCI/MSI-HOWTO.txt
<snip>
> +4.3.1 pci_enable_msix
> +
> +int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec)
> +
> +Calling this function asks the PCI subsystem to allocate 'nvec' MSIs.
> +The 'entries' argument is a pointer to an array of msix_entry structs
> +which should be at least 'nvec' entries in size. On success, the
> +function will return 0 and the device will have been switched into
> +MSI-X interrupt mode. The 'vector' elements in each entry will have
> +been filled in with the interrupt number. The driver should then call
> +request_irq() for each 'vector' that it decides to use.
> +
> +If this function returns a negative number, it indicates an error and
> +the driver should not attempt to allocate any more MSI-X interrupts for
> +this device. If it returns a positive number, it indicates the maximum
> +number of interrupt vectors that could have been allocated.
.. that perhaps we should have an example here. eg:
static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
{
while (nvec >= FOO_DRIVER_MINIMUM_NVEC) {
rc = pci_enable_msix(adapter->pdev, adapter->msix_entries, nvec);
if (rc > 0)
nvec = rc;
else
return rc;
}
return -ENOSPC;
}
To at least plant the seed in driver writers' minds that they should try
and support a variable number of MSI-X.
cheers
--
Michael Ellerman
OzLabs, IBM Australia Development Lab
wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)
We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person
Attachment:
signature.asc
Description: This is a digitally signed message part
