From: George Kadianakis Date: Sun, 17 Jan 2010 19:19:31 +0000 (+0200) Subject: [SCSI] lpfc: restore MSI-X/MSI support X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=8605c46c171f02859fb3a32655fa226ce446c6ec;p=deliverable%2Flinux.git [SCSI] lpfc: restore MSI-X/MSI support A Gentoo bug report [1] showed that as of 2.6.31 lpfc only uses INTx interrupts. This patch restores lpfc's ability to support MSI-X/MSI interrupts that the "Addition of SLI4 Interface - Base Support" patch [2] broke. It reestablishes MSI-X as the default interrupt method and in case MSI-X is not supported lpfc_sli{4,}_enable_intr fallbacks to MSI and then to INTx. [1]: http://bugs.gentoo.org/show_bug.cgi?id=296319 [2]: commit da0436e915a5c17ee79e72c1bf978a4ebb1cbf4d [James Smart: Background: Nothing Broke. This was intended. We had originally enabled MSI-X by default, but in qualification within the last 12 months, we encountered a major catch-22: There were at least 4 platforms, from 2 major OEMs, that : - Say they support MSI-X - platform routines work and act as if they do. - We enable it, generate a test interrupt to check they really do deliver it, and it works. - But shortly after attachment, the system hangs or loses interrupts, resulting in a bad system behavior. Given the distro's picking up the 2.6.32 kernel, we had to stick with a default of MSI-X off, with user-enabled MSI-X as these platforms couldn't get fixed. However, we're also now encountering platforms that require MSI-X and never INTx, so we must change. It's desired also for also for performance reasons. So - now (2.6.33) is the right time to re-enable MSI-X by default. ] [jejb: fix up comment on default values] Signed-off-by: George Kadianakis Acked-by: James Smart Signed-off-by: James Bottomley --- diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c index 91542f786edf..a8908e7c368a 100644 --- a/drivers/scsi/lpfc/lpfc_attr.c +++ b/drivers/scsi/lpfc/lpfc_attr.c @@ -3114,12 +3114,12 @@ LPFC_ATTR_RW(poll_tmo, 10, 1, 255, /* # lpfc_use_msi: Use MSI (Message Signaled Interrupts) in systems that # support this feature -# 0 = MSI disabled (default) +# 0 = MSI disabled # 1 = MSI enabled -# 2 = MSI-X enabled -# Value range is [0,2]. Default value is 0. +# 2 = MSI-X enabled (default) +# Value range is [0,2]. Default value is 2. */ -LPFC_ATTR_R(use_msi, 0, 0, 2, "Use Message Signaled Interrupts (1) or " +LPFC_ATTR_R(use_msi, 2, 0, 2, "Use Message Signaled Interrupts (1) or " "MSI-X (2), if possible"); /*