diff options
Diffstat (limited to 'drivers/irqchip')
| -rw-r--r-- | drivers/irqchip/irq-gic-v3-its-pci-msi.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/irqchip/irq-gic-v3-its-pci-msi.c b/drivers/irqchip/irq-gic-v3-its-pci-msi.c index 75c3cafabc6a..8d6d009d1d58 100644 --- a/drivers/irqchip/irq-gic-v3-its-pci-msi.c +++ b/drivers/irqchip/irq-gic-v3-its-pci-msi.c @@ -66,7 +66,7 @@ static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev, { struct pci_dev *pdev, *alias_dev; struct msi_domain_info *msi_info; - int alias_count = 0; + int alias_count = 0, minnvec = 1; if (!dev_is_pci(dev)) return -EINVAL; @@ -86,9 +86,17 @@ static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev, /* ITS specific DeviceID, as the core ITS ignores dev. */ info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev); - /* Allocate at least 32 MSIs, and always as a power of 2 */ + /* + * Always allocate a power of 2, and special case device 0 for + * broken systems where the DevID is not wired (and all devices + * appear as DevID 0). For that reason, we generously allocate a + * minimum of 32 MSIs for DevID 0. If you want more because all + * your devices are aliasing to DevID 0, consider fixing your HW. + */ nvec = max(nvec, alias_count); - nvec = max_t(int, 32, roundup_pow_of_two(nvec)); + if (!info->scratchpad[0].ul) + minnvec = 32; + nvec = max_t(int, minnvec, roundup_pow_of_two(nvec)); return msi_info->ops->msi_prepare(domain->parent, dev, nvec, info); } |