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Make sure that the controller is runtime resumed when system suspending to avoid an external abort when accessing the interrupt registers: Unhandled fault: external abort on non-linefetch (0x1008) at 0xd025840a ... [<c05481a4>] (musb_default_readb) from [<c0545abc>] (musb_disable_interrupts+0x84/0xa8) [<c0545abc>] (musb_disable_interrupts) from [<c0546b08>] (musb_suspend+0x38/0xb8) [<c0546b08>] (musb_suspend) from [<c04a57f8>] (platform_pm_suspend+0x3c/0x64) This is easily reproduced on a BBB by enabling the peripheral port only (as the host port may enable the shared clock) and keeping it disconnected so that the controller is runtime suspended. (Well, you would also need to the not-yet-merged am33xx-suspend patches by Dave Gerlach to be able to suspend the BBB.) This is a regression that was introduced by commit1c4d0b4e18("usb: musb: Remove pm_runtime_set_irq_safe") which allowed the parent glue device to runtime suspend and thereby exposed a couple of older issues: Register accesses without explicitly making sure the controller is runtime resumed during suspend was first introduced by commitc338412b5d("usb: musb: unconditionally save and restore the context on suspend") in 3.14. Commita1fc1920aa("usb: musb: core: make sure musb is in RPM_ACTIVE on resume") later started setting the RPM status to active during resume, and this was also implicitly relying on the parent always being active. Since commit71723f9546("PM / runtime: print error when activating a child to unactive parent") this now also results in the following warning: musb-hdrc musb-hdrc.0: runtime PM trying to activate child device musb-hdrc.0 but parent (47401400.usb) is not active This patch has been verified on 4.13-rc2, 4.12 and 4.9 using a BBB (the dsps glue would always be active also in 4.8). Fixes:c338412b5d("usb: musb: unconditionally save and restore the context on suspend") Fixes:a1fc1920aa("usb: musb: core: make sure musb is in RPM_ACTIVE on resume") Fixes:1c4d0b4e18("usb: musb: Remove pm_runtime_set_irq_safe") Cc: stable <stable@vger.kernel.org> # 4.8+ Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Daniel Mack <zonque@gmail.com> Cc: Dave Gerlach <d-gerlach@ti.com> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Tony Lindgren <tony@atomide.com> Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Bin Liu <b-liu@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.