Re: [PM-WIP-OPP][PATCH 1/4] omap3: pm: cpufreq: BUG_ON cleanup

Nishanth Menon
2010-03-19T19:56:56Z

Kevin Hilman had written, on 03/19/2010 01:42 PM, the following:
> Felipe Balbi <me@felipebalbi.com> writes:
>
>> On Fri, Mar 19, 2010 at 10:46:54AM -0700, Kevin Hilman wrote:
>>> IMO, Using BUG* macros usually indicates improper or incomplete error
>>> handling rather than a real catastrophic system failure.
>> on the other hand a kernel oops and system hang will always get
>> noted. Rather than a WARN() which simply sits in the log buffer.
>
> Of course, but what I'm trying to avoid is making other people deal
> with a BUG inserted by a developer when proper error checking and
> recovery is what is really needed.
>
I respect your views. but a few moments of thoughts:
how would the recovery look like? I can think of 2 options here.. do
share your views:

Option 1:
if (opp_init_list(OPP_MPU, omap3_opp_def_list[0])) {
WARN("dsp OPP table registration failed");
return;
}
if (opp_init_list(OPP_L3, omap3_opp_def_list[1])) {
WARN("dsp OPP table registration failed");
return;
}
if (opp_init_list(OPP_DSP, omap3_opp_def_list[2])) {
WARN("dsp OPP table registration failed");
return;
}

Option 2:
if (opp_init_list(OPP_MPU, omap3_opp_def_list[0]))
return;
if (opp_init_list(OPP_L3, omap3_opp_def_list[1]))
goto mpu_disable;
if (opp_init_list(OPP_DSP, omap3_opp_def_list[2]))
goto l3_disable;
return;

l3_disable:
freq = 0;
while (!IS_ERR(opp = opp_find_freq_ceil(OPP_L3, &freq)) {
opp_disable(opp);
freq++;
}
mpu_disable:
freq = 0;
while (!IS_ERR(opp = opp_find_freq_ceil(OPP_MPU, &freq)) {
opp_disable(opp);
freq++;
}
WARN("Registration of OPP tables failed!!");
return;

Option 1 is a bad idea as it leaves the system in an invalid state
Option 2 is the better idea as we dont have a opp_delete option(not
required usually).

All that code for something that will almost never happen?
--
Regards,
Nishanth Menon