From: Matthew Wilcox Date: Fri, 25 Jul 2008 21:42:58 +0000 (-0600) Subject: PCI MSI: Don't disable MSIs if the mask bit isn't supported X-Git-Tag: v2.6.27-rc1~3^2~7 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ce6fce4295ba727b36fdc73040e444bd1aae64cd;p=linux-2.6 PCI MSI: Don't disable MSIs if the mask bit isn't supported David Vrabel has a device which generates an interrupt storm on the INTx pin if we disable MSI interrupts altogether. Masking interrupts is only a performance optimisation, so we can ignore the request to mask the interrupt. Signed-off-by: Matthew Wilcox Signed-off-by: Jesse Barnes --- diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 15af618d36..1835481717 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -126,7 +126,16 @@ static void msix_flush_writes(unsigned int irq) } } -static void msi_set_mask_bits(unsigned int irq, u32 mask, u32 flag) +/* + * PCI 2.3 does not specify mask bits for each MSI interrupt. Attempting to + * mask all MSI interrupts by clearing the MSI enable bit does not work + * reliably as devices without an INTx disable bit will then generate a + * level IRQ which will never be cleared. + * + * Returns 1 if it succeeded in masking the interrupt and 0 if the device + * doesn't support MSI masking. + */ +static int msi_set_mask_bits(unsigned int irq, u32 mask, u32 flag) { struct msi_desc *entry; @@ -144,8 +153,7 @@ static void msi_set_mask_bits(unsigned int irq, u32 mask, u32 flag) mask_bits |= flag & mask; pci_write_config_dword(entry->dev, pos, mask_bits); } else { - __msi_set_enable(entry->dev, entry->msi_attrib.pos, - !flag); + return 0; } break; case PCI_CAP_ID_MSIX: @@ -161,6 +169,7 @@ static void msi_set_mask_bits(unsigned int irq, u32 mask, u32 flag) break; } entry->msi_attrib.masked = !!flag; + return 1; } void read_msi_msg(unsigned int irq, struct msi_msg *msg)