Messages in this thread | | | From | Kevin Hilman <> | Subject | Re: [PATCH] ARM: OMAP2+: omap_device: add fail hook for runtime_pm when bad data is detected | Date | Mon, 09 Dec 2013 08:06:29 -0800 |
| |
Tony Lindgren <tony@atomide.com> writes:
> * Nishanth Menon <nm@ti.com> [131203 17:40]: >> 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. > > Kevin, any comments on this one?
Looks like a good approach to catch these corner cases.
Acked-by: Kevin Hilman <khilman@linaro.org>
| |