Paul Walmsley <paul@xxxxxxxxx> writes: > From: Tero Kristo <tero.kristo@xxxxxxxxx> > > Prevent the CORE power domain from entering RETENTION or OFF when DSS > is on. Otherwise, the display FIFO(s) may underflow due to the time > needed for the CORE to wake back up, causing tearing and unnecessary > interrupts. > > Signed-off-by: Tero Kristo <tero.kristo@xxxxxxxxx> > [paul@xxxxxxxxx: wrote commit message] > Signed-off-by: Paul Walmsley <paul@xxxxxxxxx> This isn't quite ready for merge, and needs a little more testing with current DSS driver and mainline. > --- > arch/arm/mach-omap2/cpuidle34xx.c | 10 ++++++++-- > 1 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/mach-omap2/cpuidle34xx.c b/arch/arm/mach-omap2/cpuidle34xx.c > index 0335cd8..d1b7789 100644 > --- a/arch/arm/mach-omap2/cpuidle34xx.c > +++ b/arch/arm/mach-omap2/cpuidle34xx.c > @@ -9,8 +9,9 @@ > * Copyright (C) 2007 Texas Instruments, Inc. > * Karthik Dasu <karthik-dp@xxxxxx> > * > - * Copyright (C) 2006 Nokia Corporation > + * Copyright (C) 2006, 2011 Nokia Corporation > * Tony Lindgren <tony@xxxxxxxxxxx> > + * Tero Kristo <tero.kristo@xxxxxxxxx> > * > * Copyright (C) 2005 Texas Instruments, Inc. > * Richard Woodruff <r-woodruff2@xxxxxx> > @@ -268,6 +269,12 @@ static int omap3_enter_idle_bm(struct cpuidle_device *dev, > goto select_state; > } > > + /* If DSS is active, prevent CORE RET/OFF */ > + dss_state = pwrdm_read_pwrst(dss_pd); > + if (dss_state == PWRDM_POWER_ON && > + core_next_state != PWRDM_POWER_ON) > + core_next_state = PWRDM_POWER_INACTIVE; > + Due to sleepdeps/autodeps, when this code runs, DSS powerdomain is always on. The result is that CORE is always set to INACTIVE. A side effect of this problem is exposing a known issue with PER wakeups (UART3, GPIO). Since CORE never goes to retention/off, IO-pad wakeups are never enabled, so PER wakeups do not work. I think we need a different way of checking for DSS activity. Sounds like another usecase for idle notifiers. Kevin -- 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
