Date: Wed, 17 Feb 2021 22:12:26 GMT From: Warner Losh <imp@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 955b6109bb36 - main - uart: only use MSI on devices that advertise 1 MSI vector Message-ID: <202102172212.11HMCQqq086018@gitrepo.freebsd.org>
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The branch main has been updated by imp: URL: https://cgit.FreeBSD.org/src/commit/?id=955b6109bb36036e9357006be42dfa89cd7cb0f2 commit 955b6109bb36036e9357006be42dfa89cd7cb0f2 Author: Warner Losh <imp@FreeBSD.org> AuthorDate: 2021-02-17 22:08:19 +0000 Commit: Warner Losh <imp@FreeBSD.org> CommitDate: 2021-02-17 22:08:19 +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 --- 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;
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