On 11/19/2012 9:45 PM, Jon Hunter wrote: > > On 11/16/2012 08:44 PM, Joel A Fernandes wrote: >> Hi Jon, >> >> On Fri, Nov 16, 2012 at 6:12 PM, Jon Hunter <jon-hunter@xxxxxx> wrote: >>>> diff --git a/arch/arm/mach-omap2/clock33xx_data.c >>>> b/arch/arm/mach-omap2/clock33xx_data.c >>>> index b7b7995..d0b4313 100644 >>>> --- a/arch/arm/mach-omap2/clock33xx_data.c >>>> +++ b/arch/arm/mach-omap2/clock33xx_data.c >>>> @@ -585,6 +585,7 @@ static struct clk debugss_ick = { >>>> .clkdm_name = "l3_aon_clkdm", >>>> .parent = &dpll_core_m4_ck, >>>> .ops = &clkops_omap2_dflt, >>>> + .flags = ENABLE_ON_INIT, >>>> .enable_reg = AM33XX_CM_WKUP_DEBUGSS_CLKCTRL, >>>> .enable_bit = AM33XX_MODULEMODE_SWCTRL, >>>> .recalc = &followparent_recalc, >>> >>> Does this mean this clock will always be enabled, even when not using >>> JTAG? If so, is that what you want? >> >> Yes, the clock will always be on, because some times we connect JTAG >> on a running Linux system without powering it down. I can't comment >> without doing measurements if keeping the clock on has significant >> impact on power, but I see what you mean. Definitely low power is a >> parameter and folks who want lowest possible power might need to turn >> off the clock and not have JTAG in production, but that depends on the >> user's requirement. I personally don't care about power as much as I >> care about not being able to JTAG, and I think there are other folks >> who suffer from the same JTAG problem who wouldn't necessarily want >> lowest power. > > I can't say I am that familiar with the AM33xx architecture, but I know > that on OMAP this would keep on the debugss clock and power domain. > > Do you need this change to connect JTAG after the kernel has booted or > just to maintain JTAG during kernel boot? > > I am wondering if you should implement a new flag such as > "DONT_DISABLE_ON_INIT" so if the clock is on it is not disabled, but if > it is not enabled, you don't enabled it. Then that would be the best of > both worlds. > Joel, The it should be handled is, on kernel_debug option we should keep it enabled and default it should be disabled. Something similar to, diff --git a/arch/arm/mach-omap2/clock33xx_data.c b/arch/arm/mach-omap2/clock33xx_data.c index 17e3de5..60e0b53 100644 --- a/arch/arm/mach-omap2/clock33xx_data.c +++ b/arch/arm/mach-omap2/clock33xx_data.c @@ -584,6 +584,9 @@ static struct clk debugss_ick = { .clkdm_name = "l3_aon_clkdm", .parent = &dpll_core_m4_ck, .ops = &clkops_omap2_dflt, +#ifdef CONFIG_DEBUG_KERNEL + .flags = ENABLE_ON_INIT, +#endif .enable_reg = AM33XX_CM_WKUP_DEBUGSS_CLKCTRL, .enable_bit = AM33XX_MODULEMODE_SWCTRL, .recalc = &followparent_recalc, Can you please test above change?? Thanks, Vaibhav >>> I was not sure if you are concerned about power at all. Or if having >>> that always enabled can inhibit low power states for suspend/idle etc. >> >> Maybe, suspend/resume code can turn off clock on suspend and enable it >> on resume. > > Yes, but not ideal for a product assuming they are power sensitive. > > Cheers > Jon > -- > 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 > -- 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