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This reverts commit e87efc44dd36ba3db59847c418354711ebad779b which was upstream commit 4ec7cece87b3ed21ffcd407c62fb2f151a366bc1. From Dietmar May's report on the stable mailing list (https://www.spinics.net/lists/stable/msg272201.html): > I've run into some problems which appear due to (a) recent patch(es) on > the wlcore wifi driver. > > 4.4.160 - commit 3fdd34643ffc378b5924941fad40352c04610294 > 4.9.131 - commit afeeecc764436f31d4447575bb9007732333818c > > Earlier versions (4.9.130 and 4.4.159 - tested back to 4.4.49) do not > exhibit this problem. It is still present in 4.9.141. > > master as of 4.20.0-rc4 does not exhibit this problem. > > Basically, during client association when in AP mode (running hostapd), > handshake may or may not complete following a noticeable delay. If > successful, then the driver fails consistently in warn_slowpath_null > during disassociation. If unsuccessful, the wifi client attempts multiple > times, sometimes failing repeatedly. I've had clients unable to connect > for 3-5 minutes during testing, with the syslog filled with dozens of > backtraces. syslog details are below. > > I'm working on an embedded device with a TI 3352 ARM processor and a > murata wl1271 module in sdio mode. We're running a fully patched ubuntu > 18.04 ARM build, with a kernel built from kernel.org's stable/linux repo <https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.9.y&id=afeeecc764436f31d4447575bb9007732333818c>. > Relevant parts of the kernel config are included below. > > The commit message states: > > > /I've only seen this few times with the runtime PM patches enabled so > > this one is probably not needed before that. This seems to work > > currently based on the current PM implementation timer. Let's apply > > this separately though in case others are hitting this issue./ > We're not doing anything explicit with power management. The device is an > IoT edge gateway with battery backup, normally running on wall power. The > battery is currently used solely to shut down the system cleanly to avoid > filesystem corruption. > > The device tree is configured to keep power in suspend; but the device > should never suspend, so in our case, there is no need to call > wl1271_ps_elp_wakeup() or wl1271_ps_elp_sleep(), as occurs in the patch. Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.