Re: 2.6.16-rc5: known regressions [TP 600X S3, vanilla DSDT]

Sanjoy Mahajan
2006-03-10T06:27:11Z

> I assume you have tested ec_intr=0 and ec_intr=1.

Right: I forgot to mention it, but I did test it both ways, and
ec_intr=0 is fine.

>> These noises happen when printing via the wireless card or via USB
>> (to a different HP inkjet),

> Interesting, open bug for this.

I cannot reproduce it with the vanilla DSDT, only with the modified
one. But:

> The ground rule is Don't use modified DSDT.
> If you do that, the results won't be trusted.

>> exregion-0290 [36] ex_system_io_space_han: system_iO 1 (8
>> width) Address=00000000000000B2
>>
>> repeated endlessly.

> I need calltrace for this

Looking at /proc/acpi/debug_level, I see several debugging choices
that might give the calltrace you want. Let me know which ones are
essential (I'd turn all of them on; however, I found when trying to
track this down earlier that the bug would slither away if I had too
much debugging turned on):

ACPI_LV_DISPATCH 0x00000100 [ ]
ACPI_LV_EXEC 0x00000200 [ ]
ACPI_LV_NAMES 0x00000400 [ ]
ACPI_LV_FUNCTIONS 0x00200000 [ ]

By the way, a long standing buglet for me is that 'cat
/proc/acpi/debug_level' truncates the output to 1024 bytes. So I have
to do 'cat /proc/acpi/debug_level | cat' so that the first cat doesn't
find that its stdout is a tty and try to reduce its buffer size from
4096 (big enough) to 1024. A patch is available at
<http://bugzilla.kernel.org/show_bug.cgi?id=5076>

> BTW, do you still think this is a regression?

I'm 95% sure, because booting with ec_intr=0 avoids the problem, so
the commit that made ec_intr=1 the default almost certainly also makes
this bug appear.

-Sanjoy

`Never underestimate the evil of which men of power are capable.'
--Bertrand Russell, _War Crimes in Vietnam_, chapter 1.