From 6dcfc3daab7c1c459b36261163b4e1dc15a6e965 Mon Sep 17 00:00:00 2001 From: Phil Elwell Date: Wed, 3 Feb 2016 16:12:54 +0000 Subject: [PATCH 141/170] BCM270X_DT: Disable DMA for bcm2835-sdhost on Pi2 This is an interim patch to verify that problems seen with some cards can be worked around at the expense of an increased CPU load by forcing PIO mode. Although this could have used the brcm,force-pio attribute, that is a boolean (true if present, false if absent) and attributes can't be deleted by overlays. Instead, make brcm,pio-limit unfeasibly high instead to allow DMA to be re-enabled using the pio_limit parameter of the sdhost or sdtweak overlays. --- arch/arm/boot/dts/bcm2709-rpi-2-b.dts | 1 + 1 file changed, 1 insertion(+) --- a/arch/arm/boot/dts/bcm2709-rpi-2-b.dts +++ b/arch/arm/boot/dts/bcm2709-rpi-2-b.dts @@ -43,6 +43,7 @@ pinctrl-names = "default"; pinctrl-0 = <&sdhost_pins>; bus-width = <4>; + brcm,pio-limit = <0x7fffffff>; status = "okay"; };