On Thu, Jul 4, 2013 at 9:07 PM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: >> This appears to be coming from acpi_evaluate_object_typed in >> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/char/tpm/tpm_ppi.c#n75, >> so I added a printk to get the actual value of |status| when it fails >> and it's 5 (aka AE_NOT_FOUND I believe). In hindsight, the error was somewhat obvious. The driver is locating the TPM object in the ACPI tables by walking the tables with a callback [1]. The callback is using strstr to look for the substring "TPM" in the handle of the object and returns the first that it finds. On my system, if I alter the callback to print each match and not abort the walk I find three values: \_SB_.PCI0.TPMX \_SB_.PCI0.LPCB.TPM_ \_SB_.PCI0.ITPM Of these, the second is the right one. (I note that the callback also appears to have a memory leak in the case that the string doesn't contain "TPM".) I'm sure that the strstr() worked on the computer that it was developed on, but it's rather fragile. I can get it working for me by using "LPCB.TPM" as the argument to strstr(), but who's to say that doesn't break someone else? So I would submit a patch if I was more confident that I was actually improving matters by doing so! [1] http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/char/tpm/tpm_ppi.c#n27 Cheers AGL -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
