Messages in this thread | | | Date | Mon, 16 Aug 2004 10:11:31 -0400 | From | Luben Tuikov <> | Subject | Re: VPD in sysfs |
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Matthew Wilcox wrote: > > I've been sent a patch that reads some VPD from the Symbios NVRAM and > displays it in sysfs. I'm not sure whether the way the author chose > to present it is the best. They put it in 0000:80:01.0/host0/vpd_name > which seems a bit too scsi-specific and insufficiently forward-looking > (I bet we want to expose more VPD data than that in the future, so we > should probably use a directory). > > I actually have a feeling (and please don't kill me for saying this), that > we should add a struct vpd * to the struct device. Then we need something > like the drivers/base/power/sysfs.c file (probably drivers/base/vpd.c) > that takes care of adding vpd to each device that wants it. > > Thoughts? Since there's at least four and probably more ways of getting > at VPD, we either need to fill in some VPD structs at initialisation or > have some kind of vpd_ops that a driver can fill in so the core can get > at the data.
I like this idea. Certain VPD parameters are standard across SCSI devices, so they could be shown in a standard way.
Not sure on the format of vpd_ops, _but_ getting the VPD data via the EVPD bit in INQUIRY, could be pretty standard method, so that if the LLDD doesn't set vpd_ops, they could be set to point to the (this) generic way*. (The LLDD can snoop the INQUIRY data if it wishes to, for further control.)
*I.e. the vpd_ops method(s) would be generic enough to abstract out the actual method of getting the VPD...
Certainly, providing a vpd node in sysfs would help user level apps id devices more easily. This could also be used by multipathing sofware and other apps. I think it's a good idea.
Luben
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