From mboxrd@z Thu Jan 1 00:00:00 1970 From: festevam@gmail.com (Fabio Estevam) Date: Tue, 30 Sep 2014 08:42:21 -0300 Subject: [PATCH] ARM: mx6: Fix suspend/resume with PCI In-Reply-To: References: <1407371998-11437-1-git-send-email-festevam@gmail.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Bj?rn, On Tue, Sep 30, 2014 at 7:12 AM, Bj?rn Erik Nilsen wrote: > Hi Fabio, > > On Wed, 2014-08-06 at 21:39 -0300, an unknown sender wrote: >> From: Fabio Estevam >> >> When PCI is used and a suspend/resume sequence is done we see the following >> kernel hang: >> >> root at freescale /$ echo mem > /sys/power/state >> [ 16.099018] PM: Syncing filesystems ... done. >> [ 16.141010] Freezing user space processes ... (elapsed 0.002 seconds) done. >> [ 16.150840] Freezing remaining freezable tasks ... (elapsed 0.003 seconds) done. >> [ 16.199438] random: nonblocking pool is initialized >> [ 16.229639] PM: suspend of devices complete after 64.793 msecs >> [ 16.235488] PM: suspend devices took 0.070 seconds >> [ 16.245301] PM: late suspend of devices complete after 4.968 msecs >> [ 16.257063] PM: noirq suspend of devices complete after 5.538 msecs >> [ 16.263425] Disabling non-boot CPUs ... >> [ 16.274666] CPU1: shutdown >> [ 16.286351] CPU2: shutdown >> [ 16.294169] CPU3: shutdown >> [ 16.299551] Enabling non-boot CPUs ... >> [ 16.304155] CPU1: Booted secondary processor >> [ 16.305717] CPU1 is up >> [ 16.313078] CPU2: Booted secondary processor >> [ 16.313456] CPU2 is up >> [ 16.320778] CPU3: Booted secondary processor >> [ 16.321174] CPU3 is up >> (hangs here) >> >> Implement a workaround for the erratum ERR005723: "PCIe does not support L2 >> Power Down", which consists in toggling bit 18 (TEST_POWERDOWN) of GPR1 register. >> >> Tested on a mx6qsabresd TO1.2 revC2. >> >> Reported-by: Shawn Guo >> Signed-off-by: Fabio Estevam > > Tested-by: Bj?rn Erik Nilsen > > I encountered exactly the same problem and can confirm your patch works. > > Thank you! > > I hope this patch (or one that is considered a proper solution) will > make it to the mainline kernel any time soon. Thanks for testing. This is a workaround found on FSL kernel. We still need to come up with a proper fix for this PCI suspend/resume issue.