Messages in this thread | | | Date | Mon, 21 May 2007 11:09:03 +0200 | From | Tejun Heo <> | Subject | Re: something strange in libata-core.c for kernel 2.6.22-rc3 |
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Robert Hancock wrote: >> Alan, did you have a chance to test the ACPI cable detection? It just >> didn't work when I tried it. It always returned 80c on my machine. > > On a whim I started poking around in the disassembled ACPI DSDT code for > my Asus A8N-SLI Deluxe board, which is one of these chipsets. The > original thought was that the STM/GTM trick on these chipsets is > supposed to allow us to determine what modes we should use based on what > modes it sets up appropriately. Unfortunately, unless I'm missing > something in the AML (which is possible) it doesn't seem like there is > any validation being done on the settings passed in. The settings appear > to essentially just get programmed into the controller when STM is > called and read back on GTM.
Yeah, that's consistent to what I've seen on my machine which is a variant of A8N. No matter what value I through at _STM, _GTM just echoed the result thus always leading to 80c configuration.
> I guess this means that what we have to do is trust that the BIOS set up > a reasonable mode and base the cable detect on that (either by reading > back the boot-up controller registers, or by calling GTM). I imagine > this is what the Windows default IDE driver is doing (just using the > boot-up mode and feeding it back using GTM/STM on suspend/resume cycles).
Alan, what do you think?
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