IMX53 on recent 4.4.x kernels

[Fabio Estevam]

Hi Russell,

On Thu, Jul 20, 2017 at 8:53 PM, Russell King - ARM Linux
<linux at armlinux.org.uk> wrote:

> Another thing to check is that you have features like the spinlock
> debug, semaphore debug, lockdep, tracing etc all disabled - these
> can add quite a bit of additional processing into critical paths.

Yes, this really helps.

On my tests with Noel's application the execution time goes from 41 to
22 seconds on kernel 4.13-rc1.

Here is the defconfig changes generated by manually removing these
features and then using savedefconfig:

diff --git a/arch/arm/configs/imx_v6_v7_defconfig
b/arch/arm/configs/imx_v6_v7_defconfig
index 49e7969..21a37bd 100644
--- a/arch/arm/configs/imx_v6_v7_defconfig
+++ b/arch/arm/configs/imx_v6_v7_defconfig
@@ -9,6 +9,7 @@ CONFIG_CGROUPS=y
 CONFIG_RELAY=y
 CONFIG_BLK_DEV_INITRD=y
 CONFIG_EXPERT=y
+CONFIG_KALLSYMS_ALL=y
 CONFIG_PERF_EVENTS=y
 # CONFIG_SLUB_DEBUG is not set
 # CONFIG_COMPAT_BRK is not set
@@ -80,7 +81,6 @@ CONFIG_CAN_FLEXCAN=y
 CONFIG_BT=y
 CONFIG_BT_HCIUART=y
 CONFIG_BT_HCIUART_H4=y
-CONFIG_BT_HCIUART_LL=y
 CONFIG_CFG80211=y
 CONFIG_CFG80211_WEXT=y
 CONFIG_MAC80211=y
@@ -166,9 +166,9 @@ CONFIG_MOUSE_PS2_ELANTECH=y
 CONFIG_INPUT_TOUCHSCREEN=y
 CONFIG_TOUCHSCREEN_ADS7846=y
 CONFIG_TOUCHSCREEN_EGALAX=y
+CONFIG_TOUCHSCREEN_MAX11801=y
 CONFIG_TOUCHSCREEN_IMX6UL_TSC=y
 CONFIG_TOUCHSCREEN_EDT_FT5X06=y
-CONFIG_TOUCHSCREEN_MAX11801=y
 CONFIG_TOUCHSCREEN_MC13783=y
 CONFIG_TOUCHSCREEN_TSC2004=y
 CONFIG_TOUCHSCREEN_TSC2007=y
@@ -177,7 +177,6 @@ CONFIG_TOUCHSCREEN_SX8654=y
 CONFIG_TOUCHSCREEN_COLIBRI_VF50=y
 CONFIG_INPUT_MISC=y
 CONFIG_INPUT_MMA8450=y
-CONFIG_HID_MULTITOUCH=y
 CONFIG_SERIO_SERPORT=m
 # CONFIG_LEGACY_PTYS is not set
 CONFIG_SERIAL_IMX=y
@@ -237,7 +236,6 @@ CONFIG_V4L_PLATFORM_DRIVERS=y
 CONFIG_SOC_CAMERA=y
 CONFIG_V4L_MEM2MEM_DRIVERS=y
 CONFIG_VIDEO_CODA=m
-CONFIG_SOC_CAMERA_OV2640=y
 CONFIG_IMX_IPUV3_CORE=y
 CONFIG_DRM=y
 CONFIG_DRM_PANEL_SIMPLE=y
@@ -274,6 +272,7 @@ CONFIG_SND_SOC_CS42XX8_I2C=y
 CONFIG_SND_SOC_TLV320AIC3X=y
 CONFIG_SND_SOC_WM8960=y
 CONFIG_SND_SIMPLE_CARD=y
+CONFIG_HID_MULTITOUCH=y
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_EHCI_MXC=y
@@ -388,7 +387,7 @@ CONFIG_PRINTK_TIME=y
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
 # CONFIG_SCHED_DEBUG is not set
-CONFIG_PROVE_LOCKING=y
+CONFIG_STACKTRACE=y
 # CONFIG_DEBUG_BUGVERBOSE is not set
 # CONFIG_FTRACE is not set
 # CONFIG_ARM_UNWIND is not set
-- 
2.7.4