From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Subject: Re: Suspend/Resume issue in 4.8-rc8 Date: Mon, 10 Oct 2016 15:07:06 +0300 Message-ID: <20161010120706.GA3853@intel.com> References: <147608140340.2733.12285605928656228981@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <147608140340.2733.12285605928656228981@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org To: Genki Marshall Cc: Jason Gunthorpe , Peter Huewe , Marcel Selhorst , tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org List-Id: tpmdd-devel@lists.sourceforge.net On Mon, Oct 10, 2016 at 02:36:43AM -0400, Genki Marshall wrote: > Hello, > > On 4.8-rc8, I'm having an issue with laptop suspend/resume for the > Chromebook Pixel (2015). Specifically: > > When on commit 24532f7 on Linus's tree (latest commit at time of > writing) I'm having the following issue happen consistently: > > 1. Close lid. > 2. Wait for CPU to wind down and laptop lid's light to go off. > 3. Open lid. > 4. Observe that the computer is booting from scratch. > > I noticed that 4.8-rc7 was working fine. Bisecting, I found 0c54133 to > be the commit at which this issue starts happening, which is a > patch to drivers/char/tpm/tpm-interface.c . > > I confirmed this is still relevant as I can proceed to checkout > 24532f7 again, do a git revert 0c54133, recompile, and the issue no > longer happens. > > It's a very small patch. Looking through the code, it's strange, as it > seems to use the tpm_pcr_read_dev() helper correctly (to my totally > untrained eye). > > In the version with 0c54133 _reverted_, when I make the values of 'rc' > be printed, recompile, and then resume my laptop (which again, it does > successfully), I see the values go like: > > rc = tpm_transmit(chip, (u8 *) &cmd, READ_PCR_RESULT_SIZE, 0); > /* rc == 30 here */ > ... > rc = be32_to_cpu(cmd.header.out.return_code); > /* rc == 0 here */ > > So it returns 0 correctly as expected. But tpm_transmit_cmd() looks > like it should do effectively the same thing (calling tpm_transmit() > then calling be32_to_cpu()), and it would just be that rc == 0 right > away. It started to be difficult to debug as I can't see the results > of prints when resuming on the broken tree (as it goes straight to > rebooting). > > Anyway, I was advised on #kernel-newbies that at this point it would > be best to just email in like this. Let me know if it would be helpful > for me to answer/test anything. Sure. Thank you for sending this and taking time to provide a detailed description. I'll come back to this ASAP. > Genki Email is fine. I also try to track bugzilla.kernel.org for TPM related bugs. /Jarkko