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PCI MSI: Don't disable MSIs if the mask bit isn't supported

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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 <willy@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Matthew Wilcox 2008-07-25 15:42:58 -06:00 committed by Jesse Barnes
parent 29111f579f
commit ce6fce4295
1 changed files with 12 additions and 3 deletions
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15
drivers/pci/msi.c
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@ -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)