Messages in this thread | | | Date | Mon, 11 Sep 2006 19:21:11 +0400 | From | Sergei Shtylyov <> | Subject | Re: What's in libata-dev.git |
| |
Hello.
Alan Cox wrote:
>>>drivers/ide. You might want to do 256 for SATA Jeff but please don't do >>>256 for PATA. Reading specs is too hard for some people ;)
>>>Some drives abort the xfer, some just choked.
>>Where in drivers/ide is it limited to 255?
> Being a sensible sanity check it was removed, and that was a small > mistake. Some 2.4 also has a 256 limit and it broken various transparent > raid units, older Maxtors(1Gb or so), some IBM drives etc. Got fixed in > -ac but never in base.
> The failure pattern is pretty ugly too, your box runs and runs and > eventually you get a linear 256 sector I/O and it all blows up, > sometimes. The IBM's abort the xfer but the maxtors may or may not get > it right (its as if half the firmware has the right test).
So, this seems to have a long history... :-) I've also heard several years ago of the drives not getting anything over 128 sectors right, but those should be really brain-damaged...
> We could perhaps do it by ATA version - 255 for ATA < 3 256 for ATA 3+,
Wouldn't work, I'm afraid. That IBM drive is UltraATA/33, so no less than ATA-4... Well, after having referred to the ID data read from it, it's ATA-3 actually.
> lots for LBA48 ? Thats assuming you can show 256 sectors is faster than > 255. I'd bet for normal I/O its unmeasurably small.
> Alan
WBR, Sergei - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |