Re: [PATCH 5/5] arm: msm: smd: fix SMD modem processor sync condition

[Dima Zavin <dima@android.com>]

On Mon, Apr 19, 2010 at 12:01 PM, Daniel Walker <dwalker@codeaurora.org> wrote:
> On Mon, 2010-04-19 at 11:34 -0700, Dima Zavin wrote:
>> Do we really need a formalized blocking point here? The apps processor
>> can do other useful initialization work while the modem is booting.
>> The first time you do a proc_comm call, it checks the PCOM_READY
>> state, and will block anyway. Preventing the apps processor from
>> continuing until then is suboptimal. If there are bugs in the modem
>> code where it incorrectly stomps on shared resources, then those
>> should be fixed. This patch looks like a hack to me.
>
>
> Yes, we need to formalize a blocking point .. The apps processor waits
> in this way no matter what you do .. Like your saying above "The first
> time you do a proc_comm call, it checks the PCOM_READY state, and will
> block anyway" that's a hack .. What your saying is _maybe_ there exists
> a proc_comm call early enough to prevent a crash, or maybe not .. That's
> not formal enough.

That's not at all what I am saying. There's no maybe. If I don't need
anything from the modem, I won't make a proc_comm call. If there is a
crash because the modem is modifying shared resources that affect the
apps processor without an appropriate synchronization point, then it's
a bug on the modem side. Making this change will only mask modem bugs.

--Dima

> This patch makes this a formal process with a comment explain what is
> happening, and we will never see a crash related to this again.
>
> Daniel
>
>