On 15.05.2013 23:50, Mark A. Greer wrote: > On Wed, May 15, 2013 at 10:07:35AM -0700, Tony Lindgren wrote: >> * Mark A. Greer <mgreer@xxxxxxxxxxxxxxx> [130514 18:57]: >>> On Tue, May 14, 2013 at 05:25:37PM -0700, Tony Lindgren wrote: >>>> Commit a819c4f1 (ARM: OMAP3: PM: Only access IVA if one exists) >>>> changed PM to not access IVA registers on omaps that don't have >>>> them. Turns out we still need to idle iva2 as otherwise iva2_pwrdm >>>> will stay on and block deeper idle states. >>>> >>>> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> >>>> >>>> --- >>>> >>>> Paul & Kevin, do you have better ideas for fixing this? >>>> >>>> --- a/arch/arm/mach-omap2/pm34xx.c >>>> +++ b/arch/arm/mach-omap2/pm34xx.c >>>> @@ -546,8 +546,10 @@ static void __init prcm_setup_regs(void) >>>> /* Clear any pending PRCM interrupts */ >>>> omap2_prm_write_mod_reg(0, OCP_MOD, OMAP3_PRM_IRQSTATUS_MPU_OFFSET); >>>> >>>> - if (omap3_has_iva()) >>>> - omap3_iva_idle(); >>>> + /* >>>> + * We need to idle iva2_pwrdm even on am3703 with no iva2. >>>> + */ >>>> + omap3_iva_idle(); >>>> >>>> omap3_d2d_idle(); >>>> } >>> >>> [Kevin, Paul, some background: Tony discovered that the am3703 needs >>> to have omap3_iva_idle() called even though its not supposed to have >>> an IVA.] >>> >>> This is potentially bad for other SoC's that don't have an IVA so I don't >>> think its the way to go. My preference would be to set the OMAP3_HAS_IVA >>> flag for the am3703 only since its the one with the bug. Maybe something >>> in id.c:omap3xxx_check_features() but I don't see any existing way to check >>> for an am3703 vs. other am37xx SoCs. Any ideas? >>> >>> Another option, I suppose, is a dts entry but I don't like that at all. >> >> It seems that iva2_pwrdm is there for all omap3 even if OMAP3_HAS_IVA >> flag is unset. And if that's the case, iva2 clocks still need to be idled >> in all cases. > > Ahh, this takes us to the "Great TI Docs Mystery" :) -- its basically > impossible to tell because despite what their docs may say, the hardware > can be quite different. I'm not sure how to proceed other than trial & > error with as many different SoCs as we can find. > >> It's possible that not all steps in omap3_iva_idle() are needed though. >> I can debug further to see which part of the omap3_iva_idle() are needed. >> >> Mark, do you have some omap3 with no iva (other than am3703) to test the >> idle states with? > > I have an am35xx which isn't supposed to have an IVA so I can test with it > (although, I'm not sure how well the kernel works on the am35xx these days). > > I'm a bit busy today but I'll try booting the am35xx tomorrow and if it > comes up, see what I can figure out. I think this issue is relevant to am3517 as you can see from this thread: http://thread.gmane.org/gmane.linux.ports.arm.omap/97903 I could boot only with your patch http://www.spinics.net/lists/arm-kernel/msg168865.html I have such a system running, so if you have any other patches/ideas to test, I would do it. Yegor -- 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
