On 10/29/2009 01:36 PM, Peter Klotz wrote:
I have the following setup: Notebook (Ubuntu 9.10, 2.6.31-14 amd64) with ICH9M controller in AHCI mode and an external storage box (Sil5744, 2 HDDs) connected via eSATA. The box supports JBOD and the manufacturer says that a Port Multiplier capable eSATA port is needed to see both HDDs. I see only one HDD. Here is part of the dmesg output from startup: [ 0.725096] ahci 0000:00:1f.2: AHCI 0001.0200 32 slots 4 ports 3 Gbps 0x23 impl SATA mode [ 0.725099] ahci 0000:00:1f.2: flags: 64bit ncq sntf stag pm led clo pio slum part ems The pmp flag is not present but several sources claim that ICH9 supports Port Multiplier.
It seems like it may be variable between specific ICH versions (mobile, RAID, etc.) whether they support PMP or not. Obviously in your case the controller doesn't report PMP support in the AHCI capabilities register.
Should Port Multiplier be available for ICH9M? Can I enable it somehow maybe by using a module option?
No module parameter for that, you'd have to hack the code in ahci.c to force the option on. No guarantees it's going to work if the controller doesn't report the capability, though.
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