On Tue, 2011-06-14 at 18:44 -0700, Xiangliang Yu wrote: >> Subject: Re: [PATCH] [SCSI] LIBSAS: fix libsas link error issue >> >> On Tue, 2011-06-14 at 23:17 +0800, yxlraid@xxxxxxxxx wrote: >> >> From: Xiangliang Yu <yuxiangl@xxxxxxxxxxx> >> >> >> >> -- 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@xxxxxxxxxxx> >> >> --- >> >> 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. >it's probably a negotiation problem. If the >child can't support the highest possible link rate because of problems >like transmission errors, it should fall back. I get the issue like this: 1. HBA support 3Gbps, level 1 expander support 6Gbps, and level 2 expander support 6Gbps; 2. level 1 is fine, and find that level 2 link rate is 6Gbps in DISCOVER command response. 3. LIBSAS think level 2 is 6Gbps by sas_ex_get_linkrate function, and send command to level 2 expander 4. LIBSAS link error. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
