Display debug(Blue Screen , fliker)

HW： 8x12&8x10

SW:   193513A

panel resolution: 1280*800

调试一pad项目中出现了一个问题, 在进入camera应用的时候启用ZSL（零秒快拍），会出现屏幕局部Blue Screen. 进入video recording启用time lapse recording（0.5s）,resolution在480P以下时，出现Blue Screen的概率比较高，奇怪的是在720P没有出现Blue screen，这种情况之前没有遇到过，提case给高通，对于ZSL模式回复如下：

mount -t debugfs debugfs /d 
There are two methods to verify the issue is actually an underrun problem:- 

1. By checking the MDP stats after mounting debugfs:- 

1.a) adb shell 

1.b) cd d/mdp //d is debugfs already mounted 

1.c) cat stat 

mdp: 

intf2: play: 00000000 vsync: 00006823 underrun: 00000000 

Here the underrun count will be non-zero value and will increment on MDP under run. 

这个debug method刚开始不知道是什么意思，后来结合8939平台上的debug manual,知道了这个是统计Blue screen次数的一个数值，我在samples machine上测得的结果

mdp: 
underrun: 00007219 

mdp: 
underrun: 00008835 

mdp: 
underrun: 00008835 

mdp: 
underrun: 00010538

这个值会随着Blue screen 出现的次数而增加，初始值应该是0.  qualcomm发来adsp image让我升级测试，升级步骤如下：

adb root 
sleep 5 
adb remount 
adb shell "rm etc/firmware/adsp*" 
adb push adsp.b00 /etc/firmware/ 
adb push adsp.b01 /etc/firmware/ 
adb push adsp.b02 /etc/firmware/ 
adb push adsp.b03 /etc/firmware/ 
adb push adsp.b04 /etc/firmware/ 
adb push adsp.b05 /etc/firmware/ 
adb push adsp.b06 /etc/firmware/ 
adb push adsp.b07 /etc/firmware/ 
adb push adsp.mdt /etc/firmware/ 
adb shell sync 
adb reboot 

这个升级finish后，蓝屏现象有所改善，但并没有完全解决。最后qualcomm也没有进一步的solution可以彻底解决，ZSL这项功能只好被暂时removed。

对于time lapse recording出现的blue screen,引起的原因应该和zsl模式下的相同或者相似，之后重新向qualcomm提了case,回复如下：

diff --git a/drivers/media/platform/msm/camera_v2/isp/msm_isp_util.c b/drivers/media/platform/msm/camera_v2/isp/msm_isp_util.c 
old mode 100644 
new mode 100755 
index f877da4..85951ff 
--- a/drivers/media/platform/msm/camera_v2/isp/msm_isp_util.c 
+++ b/drivers/media/platform/msm/camera_v2/isp/msm_isp_util.c 
@@ -150,6 +150,11 @@ int msm_isp_update_bandwidth(enum msm_isp_hw_client client, 
isp_bandwidth_mgr.client_info[i].ib; 
} 
} 
+ 
+ if (path->vectors[0].ib < 1600000000) { 
+ path->vectors[0].ib = 1600000000; 
+ path->vectors[0].ab = 1600000000; 
+ } 
msm_bus_scale_client_update_request(isp_bandwidth_mgr.bus_client, 
isp_bandwidth_mgr.bus_vector_active_idx); 
mutex_unlock(&bandwidth_mgr_mutex); 

这个patch并没有改善问题。接下来qualcomm发过来adsp，升级后，blue screen居然消失了，这一点让我感觉比较神奇，我想ZSL模式下的blue screen是否也会解决，测试后发现，出现blue的概率很低，但是仍然存在。会不会是systemwide的问题，于是将4个cpu效果全开：

adb shell stop thermald 
adb shell stop mpdecision 
adb shell "echo 1 > /sys/devices/system/cpu/cpu0/online" 
adb shell "echo 1 > /sys/devices/system/cpu/cpu1/online" 
adb shell "echo 1 > /sys/devices/system/cpu/cpu2/online" 
adb shell "echo 1 > /sys/devices/system/cpu/cpu3/online" 
adb shell "echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor" 
adb shell "echo performance > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor" 
adb shell "echo performance > /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor" 
adb shell "echo performance > /sys/devices/system/cpu/cpu3/cpufreq/scaling_governor" 

测试结果并没有改善这个问题。那么是否是频率或者带宽的影响呢？做如下的测试：

diff --git a/drivers/video/msm/mdss/mdp3.h b/drivers/video/msm/mdss/mdp3.h 
index 137a1b8..5d2ba49 100644 
--- a/drivers/video/msm/mdss/mdp3.h 
+++ b/drivers/video/msm/mdss/mdp3.h 
@@ -26,7 +26,7 @@ 
#include "mdss_fb.h" 

#define MDP_VSYNC_CLK_RATE 19200000 
-#define MDP_CORE_CLK_RATE 100000000 
+#define MDP_CORE_CLK_RATE 200000000 
#define KOFF_TIMEOUT msecs_to_jiffies(84) 

b) 

diff --git a/drivers/video/msm/mdss/mdp3_ctrl.c b/drivers/video/msm/mdss/mdp3_ctrl.c 
index cd0af6d..5009c1a 100644 
--- a/drivers/video/msm/mdss/mdp3_ctrl.c 
+++ b/drivers/video/msm/mdss/mdp3_ctrl.c 
@@ -352,7 +352,7 @@ static int mdp3_ctrl_res_req_bus(struct msm_fb_data_type *mfd, int status) 
u64 ab = 0; 
u64 ib = 0; 
ab = panel_info->xres * panel_info->yres * 4; 
- ab *= panel_info->mipi.frame_rate; 
+ ab *= panel_info->mipi.frame_rate*2; 
ib = (ab * 3) / 2; 
rc = mdp3_bus_scale_set_quota(MDP3_CLIENT_DMA_P, ab, ib); 
} else { 

The test combination is below: 
1)	Only a) 
2)	Only b) 
3)	Together a) and b) 

问题依旧没有得到改善。现在继续和qualcomm沟通这个问题，看接下来的解决方法