From 05a95d19cb248203acdd4e069d3eedfe597c3b49 Mon Sep 17 00:00:00 2001 From: Lexi Winter Date: Mon, 22 Apr 2024 16:09:26 -0600 Subject: [PATCH] alc(4): disable MSI-X by default on Killer cards Several users with alc(4)-based "Killer" Ethernet cards have reported issues with this driver not passing traffic, which are solved by disabling MSI-X using the provided tunable. To work around this issue, disable MSI-X by default on this card. This is done by having msix_disable default to 2, which means "auto-detect". The user can still override this to either 0 or 1 as desired. Since these are slow (1Gbps) Ethernet ICs used in low-end systems, it's unlikely this will cause any practical performance issues; on the other hand, the card not working by default likely causes issues for many new FreeBSD users who find their network port doesn't work and have no idea why. PR: 230807 MFC after: 1 week Reviewed by: imp Pull Request: https://github.com/freebsd/freebsd-src/pull/1185 --- share/man/man4/alc.4 | 6 +++++- sys/dev/alc/if_alc.c | 24 +++++++++++++++++++++++- 2 files changed, 28 insertions(+), 2 deletions(-) diff --git a/share/man/man4/alc.4 b/share/man/man4/alc.4 index 478558657799..5ce5ce97d68a 100644 --- a/share/man/man4/alc.4 +++ b/share/man/man4/alc.4 @@ -136,7 +136,11 @@ This tunable disables MSI support on the Ethernet hardware. The default value is 0. .It Va hw.alc.msix_disable This tunable disables MSI-X support on the Ethernet hardware. -The default value is 0. +The default value is 2, which means to enable or disable MSI-X based on the +card type; for "Killer" cards (E2x00) MSI-X will be disabled, while on other +cards it will be enabled. +Set this to 0 to force MSI-X to be enabled, or 1 to force it to be disabled +regardless of card type. .El .Sh SYSCTL VARIABLES The following variables are available as both diff --git a/sys/dev/alc/if_alc.c b/sys/dev/alc/if_alc.c index 86e120a8b3f6..86ae705667de 100644 --- a/sys/dev/alc/if_alc.c +++ b/sys/dev/alc/if_alc.c @@ -91,8 +91,14 @@ MODULE_DEPEND(alc, miibus, 1, 1, 1); /* Tunables. */ static int msi_disable = 0; -static int msix_disable = 0; TUNABLE_INT("hw.alc.msi_disable", &msi_disable); + +/* + * The default value of msix_disable is 2, which means to decide whether to + * enable MSI-X in alc_attach() depending on the card type. The operator can + * set this to 0 or 1 to override the default. + */ +static int msix_disable = 2; TUNABLE_INT("hw.alc.msix_disable", &msix_disable); /* @@ -1410,6 +1416,14 @@ alc_attach(device_t dev) case DEVICEID_ATHEROS_E2400: case DEVICEID_ATHEROS_E2500: sc->alc_flags |= ALC_FLAG_E2X00; + + /* + * Disable MSI-X by default on Killer devices, since this is + * reported by several users to not work well. + */ + if (msix_disable == 2) + msix_disable = 1; + /* FALLTHROUGH */ case DEVICEID_ATHEROS_AR8161: if (pci_get_subvendor(dev) == VENDORID_ATHEROS && @@ -1439,6 +1453,14 @@ alc_attach(device_t dev) default: break; } + + /* + * The default value of msix_disable is 2, which means auto-detect. If + * we didn't auto-detect it, default to enabling it. + */ + if (msix_disable == 2) + msix_disable = 0; + sc->alc_flags |= ALC_FLAG_JUMBO; /*