Re: Patch "tpm_tis: reserve chip for duration of tpm_tis_core_init" has been added to the 5.4-stable tree
From: Jerry Snitselaar
Date: Mon Dec 30 2019 - 20:03:09 EST
On Tue Dec 31 19, Jarkko Sakkinen wrote:
On Sun, 2019-12-29 at 23:41 -0800, Dan Williams wrote:
This looked like the wrong revert to me, and testing confirms that
this does not fix the problem.
As I mentioned in the original report [1] the commit that bisect flagged was:
5b359c7c4372 tpm_tis_core: Turn on the TPM before probing IRQ's
That commit moved tpm_chip_start() before irq probing. Commit
21df4a8b6018 "tpm_tis: reserve chip for duration of tpm_tis_core_init"
does not appear to change anything in that regard.
Perhaps this hardware has always had broken interrupts and needs to be
quirked off? I'm trying an experiment with tpm_tis_core.interrupts=0
workaround.
[1]: https://lore.kernel.org/linux-integrity/CAA9_cmeLnHK4y+usQaWo72nUG3RNsripuZnS-koY4XTRC+mwJA@xxxxxxxxxxxxxx/
I think for short term, yes, it is better to revert the commits
that make things more broken.
for-linus-v5.5-rc5 branch contains three commits that exactly do
this i.e. the reverts that Stefan sent and revert to Jerry's earlier
commit.
After that is out of the table it is easier to analyze how the code
should be actually refactored. Like, I have no idea when I get
local HW that can reproduce this and Jerry still seems to have the
same issue. It'd be nice make the exactly right changes instead of
reverts but situation is what it is.
The only other thought I had was moving the tpm_chip_start/stop
into tpm_tis_probe_irq_single around the tpm_tis_gen_interrupt call.
I don't know why doing the clkrun bit after setting the interrupt
register values would matter, but I'm not sure what else there is
that would be different than when that stuff was happening in
down in tpm_try_transmit. Without hardware to poke at it is hard
to get anywhere.
Please check the branch and ACK/NAK if I can add tested-by's (and
other tags).
/Jarkko