[ltp] Recently identified ThinkPad mysteriouses

[Thomas Renninger]

Hi Henrique,

I'd like to point you to some things I found out on ThinkPads the last
weeks:

 - IBM T41p shuts down, powersave, Temperature state changed to critical
   https://bugzilla.novell.com/show_bug.cgi?id=333043

   This affects a lot machines (T41(p), T42(p), T43(p), R40)
   I expect the real culprit is a confused EC (one machine had the
   problem, the other one not).
   Anyway, it seems ACPI notifies had higher priority (or did not get
   scheduled away) in former kernels. Therefore the BIOS could still
   avoid a critical thermal shutdown through lowering CPU frequency
   (_PPC) interface on older kernels, but something seem to have
   changed there...

 - Latest Lenovo ThinkPads do not like ACPI EC writes for brightness
   switching (s2ram broken)

   I've been told it only happens when brightness is set above 7.
   Don't know, but it seems to be the EC writes > 7 that lets the
   machine not wake up anymore from a s2ram.

 - Weird USB - EHCI IRQ problems on very latest Lenovo models

   Unhandled IRQ messages. Looks like an IRQ (from camera?) gets routed
   to EHCI pin also? Don't know the details and I am also not very
   familar with this..., Oliver might be able to point you to bug
   reports, AFAIK there also exist kernel.org bugs.
   This is not solved yet, AFAIK.
   If anyone knows more about this problem, that would be great...

   Attaching an USB device breaks USB and throws a calltrace
   https://bugzilla.novell.com/show_bug.cgi?id=325601

   As this seem to be a very (recent Lenovo) ThinkPad specific problem
   -> Only happens on latest ThinkPads, but back to at least
   kernel 2.6.16 until latest mainline... I hope to get some
   feedback from Lenovo ThinkPad users also seeing this.

Thanks,


   Thomas