diff options
| author | Michael Ellerman <michael@ellerman.id.au> | 2009-02-11 22:27:02 +1100 |
|---|---|---|
| committer | Jesse Barnes <jbarnes@hobbes.lan> | 2009-03-19 19:29:34 -0700 |
| commit | b5fbf53324f65646154e172af350674d5a2a1629 (patch) | |
| tree | 6310f1629c3112e240b151862b7f0b357045649e /drivers | |
| parent | 35e1801ea637810830e653ffe7ff62c7048ae03a (diff) | |
PCI/MSI: Allow arch code to return the number of MSI-X available
There is code in msix_capability_init() which, when the requested number
of MSI-X couldn't be allocated, calculates how many MSI-X /could/ be
allocated and returns that to the driver. That allows the driver to then
make a second request, with a number of MSIs that should succeed.
The current code requires the arch code to setup as many msi_descs as it
can, and then return to the generic code. On some platforms the arch
code may already know how many MSI-X it can allocate, before it sets up
any of the msi_descs.
So change the logic such that if the arch code returns a positive error
code, that is taken to be the number of MSI-X that could be allocated.
If the error code is negative we still calculate the number available
using the old method.
Because it's a little subtle, make sure the error return code from
arch_setup_msi_irq() is always negative. That way only implementations
of arch_setup_msi_irqs() need to be careful about returning a positive
error code.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/pci/msi.c | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 33adf323f064..dceea56f7342 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -42,8 +42,10 @@ int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type) list_for_each_entry(entry, &dev->msi_list, list) { ret = arch_setup_msi_irq(dev, entry); - if (ret) + if (ret < 0) return ret; + if (ret > 0) + return -ENOSPC; } return 0; @@ -487,7 +489,9 @@ static int msix_capability_init(struct pci_dev *dev, } ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX); - if (ret) { + if (ret < 0) { + /* If we had some success report the number of irqs + * we succeeded in setting up. */ int avail = 0; list_for_each_entry(entry, &dev->msi_list, list) { if (entry->irq != 0) { @@ -495,14 +499,13 @@ static int msix_capability_init(struct pci_dev *dev, } } - msi_free_irqs(dev); + if (avail != 0) + ret = avail; + } - /* If we had some success report the number of irqs - * we succeeded in setting up. - */ - if (avail == 0) - avail = ret; - return avail; + if (ret) { + msi_free_irqs(dev); + return ret; } i = 0; |