Messages in this thread |  | | | Date | Wed, 15 Jun 2011 00:15:34 -0400 | | From | Douglas Gilbert <> | | Subject | Re: [PATCH] [SCSI] LIBSAS: fix libsas link error issue |
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On 11-06-14 09:44 PM, Xiangliang Yu wrote: > Subject: Re: [PATCH] [SCSI] LIBSAS: fix libsas link error issue > > On Tue, 2011-06-14 at 23:17 +0800, yxlraid@gmail.com wrote: >>> From: Xiangliang Yu<yuxiangl@marvell.com> >>> >>> -- The value of child link rate should is minimum of link rate, or >>> command will fail if child link rate is bigger than parent link rate. >>> >>> Signed-off-by: Xiangliang Yu<yuxiangl@marvell.com> >>> --- >>> drivers/scsi/libsas/sas_expander.c | 2 +- >>> 1 files changed, 1 insertions(+), 1 deletions(-) >>> >>> diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c >>> index 874e29d..6ccca09 100644 >>> --- a/drivers/scsi/libsas/sas_expander.c >>> +++ b/drivers/scsi/libsas/sas_expander.c >>> @@ -638,7 +638,7 @@ static void sas_ex_get_linkrate(struct domain_device *parent, >>> sas_port_add_phy(port, phy->phy); >>> } >>> } >>> - child->linkrate = min(parent_phy->linkrate, child->max_linkrate); >>> + child->linkrate = min(parent_phy->linkrate, child->min_linkrate); > >> This patch doesn't look right. It will clamp the phy to the minim >> possible link rate. > Link negotiation should get the minimum.
spl2r01.pdf [Most recent SAS-3 draft for the protocol layers]
5.7.4.2.1 SAS speed negotiation sequence overview
"The SAS speed negotiation sequence establishes communications between the two phys on a physical link at the highest possible transmission rate."
That seems to suggest: min(<one_end>.max_linkrate, <other_end>.max_linkrate)
Doug Gilbert
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