On Wed, Sep 19, 2012 at 02:52:18PM +0300, Grazvydas Ignotas wrote: > On Tue, Sep 18, 2012 at 5:02 PM, Felipe Balbi <balbi@xxxxxx> wrote: > > On Tue, Sep 18, 2012 at 06:10:50PM +0530, Sourav Poddar wrote: > >> Greg's tty-next is not booting on 2420 based N800. The failure is > >> observed at serial init itself. The reason might be that n800 tries to > >> resume even though it is not suspended before. > >> > >> Reported-by: Paul Walmsley <paul@xxxxxxxxx> > >> Signed-off-by: Sourav Poddar <sourav.poddar@xxxxxx> > > > > FWIW: > > > > Reviewed-by: Felipe Balbi <balbi@xxxxxx> > > > > Paul does this fix the issue for you ? Note that it depends on a > > previous patch Sourav sent [1] > > > > [1] http://marc.info/?l=linux-omap&m=134796819607889&w=2 > > > > There's one thing that gets my attention, though, why only n800 would > > fail here ? > > > > I wonder if we should be using: > > > > pm_runtime_set_active(dev); > > pm_runtime_get_enable(dev); > > > > to prevent our runtime_resume() to be called from probe, but Sourav > > tested and it doesn't work on BeagleBoard, but it works on PandaBoard. > > > > Does it ring any bell ?? > > Well I guess it's normal resume callback is called during probe as > pm_runtime_get_sync() is called there, and according to documentation > [1], devices are assumed to be suspended before probe is called. > > According to [1], pm_runtime_set_active() should be called before > pm_runtime_enable() to indicate to the core that device is active > during probe if that's the case, I guess this means > pm_runtime_get_sync() is not needed in that case, but I'm not sure > what's the actual serial state during probe nowadays. > > [1] chapter 5 of Documentation/power/runtime_pm.txt: > The initial runtime PM status of all devices is 'suspended', but it > need not reflect the actual physical state of the device. Thus, if the > device is initially active (i.e. it is able to process I/O), its > runtime PM status must be changed to 'active', with the help of > pm_runtime_set_active(), before pm_runtime_enable() is called for the > device. this is what I mean, actually. If we remove pm_runtime_get_sync() in exchange for pm_runtime_set_active() before pm_runtime_enable(), it works on PandaBoard, but breaks BeagleBoard. -- balbi
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