From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: [PATCH 0/10] megaraid_sas: Updates for scsi-misc Date: Sun, 09 Oct 2011 20:56:59 -0400 Message-ID: <4E9242DB.7040401@interlog.com> References: <4E91A813.1070003@interlog.com> <1318169420.2998.6.camel@dabdike.int.hansenpartnership.com> Reply-To: dgilbert@interlog.com Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.infotech.no ([82.134.31.41]:37552 "EHLO smtp.infotech.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750925Ab1JJA5H (ORCPT ); Sun, 9 Oct 2011 20:57:07 -0400 In-Reply-To: <1318169420.2998.6.camel@dabdike.int.hansenpartnership.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: adam radford , linux-scsi , Bo.Yang@lsi.com On 11-10-09 10:10 AM, James Bottomley wrote: > On Sun, 2011-10-09 at 09:56 -0400, Douglas Gilbert wrote: >> On 11-10-08 09:14 PM, adam radford wrote: >>> James/Linux-scsi, >>> >>> The following patch series for megaraid_sas brings the driver up to v6.12-rc1: >>> >>> 1. Continue booting immediately if FW in FAULT at driver load time. >>> 2. Increase default cmds per lun to 256. >>> 3. Fix mismatch in megasas_reset_fusion() mutex lock-unlock. >>> 4. Remove some un-necessary code. >>> 5. Clear state change interrupts for Fusion/Invader. >>> 6. Clear FUSION_IN_RESET before enabling interrupts. >>> 7. Add support for MegaRAID 9360/9380 12GB/s controllers. >>> 8. Add multiple MSI-X vector/multiple reply queue support. >>> 9. Add driver workaround for PERC5/1068 kdump kernel panic. >>> 10. Version and Changelog update. >> >> I haven't checked all SAS HBAs in Linux but of those that I >> have checked only one doesn't support the SMP pass-through >> in the bsg driver. And that HBA driver is megaraid_sas **. > > Technically the megaraid_sas isn't really a SAS HBA, it's a RAID one > that just happens to have SAS/SATA disk attachments. None of the RAID > HBA's (including the IBM power raid) expose a BSG interface or even > attach properly to the in-kernel SAS interfaces. In JBOD mode MegaRaid SAS controllers are SAS HBAs (marketing BS aside). Their firmware has the same SMP pass-through as LSI's MPT SAS Fusion controllers. There is no reason why a MegaRaid controller user couldn't place a SAS-2 expander in front of an array of disks and make some disks available to a MegaRaid volume. Other array disks could be used by other machines and the different sets could be isolated from each other with SAS-2 zoning. The problem then would be that via a MegaRaid SAS controller a user could not monitor or control that zoning. Seems a bit wasteful to add a "real" SAS HBA just to get that capability. Many SAS HBAs (including MPT SAS Fusion controllers) do RAID 0 and 1 (and 10?) so they could be viewed as "RAID" controllers that expose a BSG interface. Doug Gilbert