From: Andrei Birjukov Date: Sun, 22 Feb 2009 22:37:21 +0000 (+0000) Subject: [ARM] at91: fix for Atmel AT91 powersaving X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=d82ad6d6833ee8248e6c34e1b9fc3c4e61e3f035;p=openwrt%2Fstaging%2Fblogic.git [ARM] at91: fix for Atmel AT91 powersaving We've discovered that our AT91SAM9260 board consumed too much power when returning from a slowclock low-power mode. RAM self-refresh is enabled in a bootloader in our case, this is how we saw a difference. Estimated ca. 30mA more on 4V battery than the same state before powersaving. After a small research we found that there seems to be a bogus sdram_selfrefresh_disable() call at the end of at91_pm_enter() call, which overwrites the LPR register with uninitialized value. Please find the suggested patch attached. This patch fixes correct restoring of LPR register of the Atmel AT91 SDRAM controller when returning from a power saving mode. Signed-off-by: Andrei Birjukov Acked-by: Andrew Victor Signed-off-by: Andrew Morton Signed-off-by: Russell King --- diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c index 9bb4f043aa22..7ac812dc055a 100644 --- a/arch/arm/mach-at91/pm.c +++ b/arch/arm/mach-at91/pm.c @@ -332,7 +332,6 @@ static int at91_pm_enter(suspend_state_t state) at91_sys_read(AT91_AIC_IPR) & at91_sys_read(AT91_AIC_IMR)); error: - sdram_selfrefresh_disable(); target_state = PM_SUSPEND_ON; at91_irq_resume(); at91_gpio_resume();