On 11/09/2020 06:41, Viswas.G@xxxxxxxxxxxxx wrote:
Hi Martin,
All raid controllers, newer HBAs, and sas expanders do this operation in the product firmware itself and there is no mass need to have it done in libsas. In that case, Will it be good to keep this in driver itself ?
pm80xx seems the most advanced HBA which uses libsas, so I doubt other
HBA drivers who use libsas support it. And one of these libsas users,
hisi_sas, does not even have firmware at all, but would like this kernel
support at some stage.
And I wouldn't expect expander kernel support, since, as you say,
expanders can support with firmware. I'm not sure if it's even possible
for the kernel (host) to support this anyway.
Thanks,
John
Regards,
Viswas G
-----Original Message-----
From: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Sent: Wednesday, September 2, 2020 6:51 AM
To: Viswas G <Viswas.G@xxxxxxxxxxxxxxxxx>
Cc: linux-scsi@xxxxxxxxxxxxxxx; Vasanthalakshmi Tharmarajan - I30664
<Vasanthalakshmi.Tharmarajan@xxxxxxxxxxxxx>; Viswas G - I30667
<Viswas.G@xxxxxxxxxxxxx>; Deepak Ukey - I31172
<Deepak.Ukey@xxxxxxxxxxxxx>; martin.petersen@xxxxxxxxxx;
yuuzheng@xxxxxxxxxx; auradkar@xxxxxxxxxx; vishakhavc@xxxxxxxxxx;
bjashnani@xxxxxxxxxx; radha@xxxxxxxxxx; akshatzen@xxxxxxxxxx
Subject: Re: [PATCH v8 2/2] pm80xx : Staggered spin up support.
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Viswas,
As a part of drive discovery, driver will initaite the drive spin up.
If all drives do spin up together, it will result in large power
consumption. To reduce the power consumption, driver provide an option
to make a small group of drives (say 3 or 4 drives together) to do the
spin up. The delay between two spin up group and no of drives to spin
up (group) can be programmed by the customer in seeprom and driver
will use it to control the spinup.
Please implement this in libsas as several people have suggested.
Thanks!
--
Martin K. Petersen Oracle Linux Engineering
.
