The RTAS IRQ fixup code relies on a less-than-clear edge condition for
verifying a given device is not using MSI or MSI-X. Make that more clear
with a comment.
Signed-off-by: Nishanth Aravamudan <n...@us.ibm.com>
Cc: Milton Miller <milt...@bga.com>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
---
arch/powerpc/platforms/pseries/msi.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/msi.c
b/arch/powerpc/platforms/pseries/msi.c
index 9434576..8c6dbbc 100644
--- a/arch/powerpc/platforms/pseries/msi.c
+++ b/arch/powerpc/platforms/pseries/msi.c
@@ -455,7 +455,12 @@ static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
return;
}
- /* No MSI -> MSIs can't have been assigned by fw, leave LSI */
+ /*
+ * No MSI -> MSIs can't have been assigned by fw, leave LSI
+ * The calls below can only provide one of two responses:
+ * < 0: if the device doesn't request MSI or MSI-X
+ * 0: if the device requests at least 1 MSI/MSI-X vector
+ */
if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) {
dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n");
return;
--
1.7.1
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