On 12/04/2013 07:09 AM, Nishanth Menon wrote: > Due to the cross dependencies between hwmod for automanaged device > information for OMAP and dts node definitions, we can run into scenarios > where the dts node is defined, however it's hwmod entry is yet to be > added. In these cases: > a) omap_device does not register a pm_domain (since it cannot find > hwmod entry). > b) driver does not know about (a), does a pm_runtime_get_sync which > never fails > c) It then tries to do some operation on the device (such as read the > revision register (as part of probe) without clock or adequate OMAP > generic PM operation performed for enabling the module. > > This causes a crash such as that reported in: > https://bugzilla.kernel.org/show_bug.cgi?id=66441 > > When 'ti,hwmod' is provided in dt node, it is expected that the device > will not function without the OMAP's power automanagement. Hence, when > we hit a fail condition (due to hwmod entries not present or other > similar scenario), fail at pm_domain level due to lack of data, provide > enough information for it to be fixed, however, it allows for the driver > to take appropriate measures to prevent crash. > > Reported-by: Tobias Jakobi <tjakobi@xxxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Nishanth Menon <nm@xxxxxx> > --- > arch/arm/mach-omap2/omap_device.c | 24 ++++++++++++++++++++++++ > arch/arm/mach-omap2/omap_device.h | 1 + > 2 files changed, 25 insertions(+) > > diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c > index 53f0735..e0a398c 100644 > --- a/arch/arm/mach-omap2/omap_device.c > +++ b/arch/arm/mach-omap2/omap_device.c > @@ -183,6 +183,10 @@ static int omap_device_build_from_dt(struct platform_device *pdev) > odbfd_exit1: > kfree(hwmods); > odbfd_exit: > + /* if data/we are at fault.. load up a fail handler */ > + if (ret) > + pdev->dev.pm_domain = &omap_device_fail_pm_domain; > + > return ret; > } > Just wondering, can't we just print the warning here instead of registering new pm_domain callbacks? Concerned that all this LOC may end up being dead code when the "ti,hwmods" property becomes obsolete anyway. -Joel -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
