Messages in this thread Patch in this message | | | Date | Tue, 7 Apr 2009 11:18:01 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [GIT PULL] Ext3 latency fixes |
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On Mon, 6 Apr 2009, Jeff Garzik wrote:
> Arjan van de Ven wrote: > > On Sun, 05 Apr 2009 16:57:21 -0400 > > Jeff Garzik <jeff@garzik.org> wrote: > > > We set it in libata-scsi.c:ata_scsi_dev_config() based on > > > ata_id_is_ssd() > > > > > > That hueristic probably assumes Intel SSDs or something :/ > > > > you mean the "rpm" set to '1' ? > > I was pretty sure that that was industry standard... > > A -new- industry standard. You can certainly create a compliant SSD while > only conforming to ATA-7, for example. Some older IDE flash devices pretend > they are normal hard drives in almost every respect, too.
Something like this might be a good idea.
I've seen several SSD's that do _not_ do that whole RPM == 1 thing, but they have "SSD" in their names.
I forget how the ID is stored (I have this memory of it being big-endian 16-bit words or something crazy like that?), but aside from fixing up that kind of crazyness, maybe something like this is worth it?
And making it non-inline, of course. And maybe it should use 'strstr()' instead of checking whether the name ends in 'SSD'. You get the idea..
Linus
--- --- a/include/linux/ata.h +++ b/include/linux/ata.h @@ -769,7 +769,14 @@ static inline int ata_id_is_cfa(const u16 *id) static inline int ata_id_is_ssd(const u16 *id) { - return id[ATA_ID_ROT_SPEED] == 0x01; + int len; + const char *model; + + if (id[ATA_ID_ROT_SPEED] == 0x01) + return 1; + model = (const char *)&id[ATA_ID_PROD]; + len = strnlen(model, ATA_ID_PROD_LEN); + return len > 3 && !memcmp(model+len-3, "SSD", 3); } static inline int ata_drive_40wire(const u16 *dev_id)
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