git: ef1f20560842 - stable/13 - uart: only use MSI on devices that advertise 1 MSI vector
Warner Losh
imp at FreeBSD.org
Wed Feb 24 18:10:03 UTC 2021
The branch stable/13 has been updated by imp:
URL: https://cgit.FreeBSD.org/src/commit/?id=ef1f2056084202c554d5482af9586a8995e604d5
commit ef1f2056084202c554d5482af9586a8995e604d5
Author: Warner Losh <imp at FreeBSD.org>
AuthorDate: 2021-02-17 22:08:19 +0000
Commit: Warner Losh <imp at FreeBSD.org>
CommitDate: 2021-02-24 17:57:07 +0000
uart: only use MSI on devices that advertise 1 MSI vector
This updates r311987/fb1d9b7f4113d which allowed any number of vectors to be
used. Since we're just attaching one instance, the meaning of more than one
vector is not clear and seems to cause problems. Fall back to old methods for
these cards.
PR: 235016
Submitted by: David Cross
(cherry picked from commit 955b6109bb36036e9357006be42dfa89cd7cb0f2)
---
sys/dev/uart/uart_bus_pci.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/sys/dev/uart/uart_bus_pci.c b/sys/dev/uart/uart_bus_pci.c
index 0ed3d7f4f974..fbd1d68b88ca 100644
--- a/sys/dev/uart/uart_bus_pci.c
+++ b/sys/dev/uart/uart_bus_pci.c
@@ -227,10 +227,10 @@ uart_pci_attach(device_t dev)
sc = device_get_softc(dev);
/*
- * Use MSI in preference to legacy IRQ if available.
- * Whilst some PCIe UARTs support >1 MSI vector, use only the first.
+ * Use MSI in preference to legacy IRQ if available. However, experience
+ * suggests this is only reliable when one MSI vector is advertised.
*/
- if (pci_msi_count(dev) > 0) {
+ if (pci_msi_count(dev) == 1) {
count = 1;
if (pci_alloc_msi(dev, &count) == 0) {
sc->sc_irid = 1;
More information about the dev-commits-src-all
mailing list