Re: Acer Aspire 7720 shutdown problems and DSDT fixes

[Alan Jenkins <alan-jenkins@tuffmail.co.uk>]

Bernhard Rosenkränzer wrote:
> Hi,
> I recently got an Acer Aspire 7720 using BIOS 1.43. Obviously, the first thing 
> to do was install Linux (currently running 2.6.27-rc4).
>
> Everything is working, but under heavy load, the machine tends to shut down 
> without prior warning. Unlike the similar problem described at 
> http://bugzilla.kernel.org/show_bug.cgi?id=9167, /proc/acpi/thermal_zone/TZ01/temperature 
> does show the correct temperature all the time, and the fan does turn on.
>
> I've looked at the DSDT and found a huge number of obvious bugs (_OSC taking 
> the wrong number of arguments and actually having an off-by-one bug when 
> looking at the arguments -- looks like someone didn't know ACPI arguments 
> start at Arg0 and then increased the argument count by 1 so he could get the 
> 4th argument in Arg4; Funny comparisons like
> If (LOr (LGreater (OSYS, 0x07D0), LLess (OSYS, 0x07D7)))
> (not that that could ever not be true...); doesn't even compile.....), but 
> fixing them doesn't help.
>
> I've tried all sorts of things to get it to behave, including patching the 
> DSDT to actually know about the fact that TZ01 is connected to the CPUs and 
> throttling the CPUs may help:
>
>             Method (_PSV, 0, Serialized)
>             {
>                 Return (3552) // 3552 = (273.2+82.0)*10
>             }
>
>             Method (_PSL, Package() {
>                 \_PR.CPU0,
>                 \_PR.CPU1
>             })
>
>             Name (_TC1, 3)
>             Name (_TC2, 4)
>             Name (_TSP, 20)
>             Name (_TZP, Zero)
>
> (This part works nicely by the way)
>
> But at some point, it still shuts down.
>
> Looking at sensors output, the box seems to shut down when it hits 85.0°C, 
> which is also what the coretemp module thinks is right (tjmax value) -- but 
> the DSDT sets the trip point at 110°C:
>
>             Method (_CRT, 0, Serialized)
>             {
>                 Return (Add (0x0AAC, Multiply (0x6E, 0x0A)))
>             }
>
> Guess this explains why I'm getting a sudden shutdown instead of a clean 
> shutdown through acpid - adjusting _CRT to return 84°C doesn't fix the 
> problem, but does let acpid shut down the system gracefully instead of just 
> going down.
>
> However, given that's what the DSDT says, my guess is the box has actually 
> been designed to run at 110°C and simply shouldn't be shutting down at 85°C 
> without warning - any ideas what may be causing this or how to fix it?
>   
In theory they sell a version with Linux preinstalled, and are
interested in engaging with Linux generally.  Maybe you can find the
kernel version, patches & Kconfig and see if their kernel is any better.

Alan
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