Android亮屏速度分析总结

前面聊的

最近在调试项目的亮屏速度，我们希望在按下power键后到亮屏这个时间能达到500MS以内，在Rockchip 3399和3288上面的时间都不能达到要求，因此引发了一系列的调试之路。

计算按下power键到亮屏的时间

Android 唤醒时间统计

刚开始的时候，我只在android阶段统计时间，也能看到时间的差异，但是不是最准确的，我统计的时间日志如下

01-18 09:13:40.992 683 772 D SurfaceControl: Excessive delay in setPowerMode(): 743ms
01-18 09:13:45.304 683 772 D SurfaceControl: Excessive delay in setPowerMode(): 757ms
01-18 09:13:49.559 683 772 D SurfaceControl: Excessive delay in setPowerMode(): 725ms
01-18 09:18:27.461 683 772 D SurfaceControl: Excessive delay in setPowerMode(): 741ms
01-18 09:18:32.766 683 772 D SurfaceControl: Excessive delay in setPowerMode(): 743ms
01-18 09:18:35.861 683 772 D SurfaceControl: Excessive delay in setPowerMode(): 745ms
01-18 09:18:38.345 683 772 D SurfaceControl: Excessive delay in setPowerMode(): 733ms

Kernel从Power到亮屏的时间统计

后来同事中的精英古总在他的代码上加入了从按下Power键到亮屏的时间，直接通过printk打印，代码如下

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.cold mode 100644new mode 100755index 17c3b94..2b39662--- a/drivers/gpu/drm/panel/panel-simple.c+++ b/drivers/gpu/drm/panel/panel-simple.c@@ -504,6 +504,7 @@ static int panel_simple_enable(struct drm_panel *panel)    }    p->enabled = true;+    printk("%s exit\n", __func__);    return 0; }diff --git a/drivers/input/keyboard/rk_keys.c b/drivers/input/keyboard/rk_keys.cold mode 100644new mode 100755index fed5ced..537b599--- a/drivers/input/keyboard/rk_keys.c+++ b/drivers/input/keyboard/rk_keys.c@@ -134,6 +134,10 @@ static void keys_timer(unsigned long _data)        key_dbg(pdata, "%skey[%s]: report event[%d] state[%d]\n",            button->type == TYPE_ADC ? "adc" : "gpio",            button->desc, button->code, button->state);+        if(strcmp(button->desc, "power") == 0)+        printk("%skey[%s]: report event[%d] state[%d]\n",+            button->type == TYPE_ADC ? "adc" : "gpio",+            button->desc, button->code, button->state);        input_event(input, EV_KEY, button->code, button->state);        input_sync(input);    }

统计每个驱动的resume函数调用时间

上面的时间对我们调试非常有用，然后就需要细分到每个驱动的resume函数执行的时间，用的方法是我之前写过的，大概统计了下TP，LCD，sensor的resume时间，发现TP和LCD占用的时间非常多，然后跟同事一起看了下，同事把TP resume里面的代码用工作队列实现后速度明显有了提升。

然后有很长一段时间不知道干嘛，向打印其他每个驱动的resume时间，一直没找到方法，后面看到一个代码，非常有用。

kernel/drivers/base/power/main.c

static void dpm_show_time(ktime_t starttime, pm_message_t state, char *info)                            {          ktime_t calltime;  u64 usecs64;  int usecs;  calltime = ktime_get();  usecs64 = ktime_to_ns(ktime_sub(calltime, starttime));  do_div(usecs64, NSEC_PER_USEC);  usecs = usecs64;  if (usecs == 0)    usecs = 1;   pr_info("PM: %s%s%s of devices complete after %ld.%03ld msecs\n",    info ?: "", info ? " " : "", pm_verb(state.event),    usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);}

这个函数用来打印resume的函数消耗的时间，但是如何去触发打印这个函数呢?

一定保证设备进入深度睡眠，串口也进入深度睡眠，没有任何打印后。
执行以下命令

echo N > /sys/module/printk/parameters/console_suspend//使控制台在suspend最后才关闭，这样可以打印出休眠过程完整信息echo 1 > /sys/power/pm_print_times//使能调试变量

打印的LOG类似下面的

[ 37.031413] bcmsdh_sdmmc_resume Exit
[ 37.082174] PM: resume of devices complete after 78.589 msecs
[ 37.085277] [BT_RFKILL]: ** disable irq
[ 37.087645] Restarting tasks ...

修改Lcd配置减小resume时间

古总在调试过程中展现了非常厉害的功底，第一步就是修改了LCD的参数，让亮屏时间加快。修改如下

--- a/arch/arm/boot/dts/rk3288-pad.dts+++ b/arch/arm/boot/dts/rk3288-pad.dts@@ -169,10 +169,10 @@        dsi,lanes = <4>;        prepare-delay-ms = <20>;-        init-delay-ms = <20>;-        enable-delay-ms = <100>;-        disable-delay-ms = <20>;-        unprepare-delay-ms = <20>;+        //init-delay-ms = <20>;+        enable-delay-ms = <1>;+        disable-delay-ms = <1>;+        unprepare-delay-ms = <1>;        panel-init-sequence = [            15 32 02 8F A5            15 01 02 83 00

修改DRM 超时时间减小唤醒时间

这是最关键的，DRM框架非常复杂，RK也是从开源的DRM移植过来使用，在DRM部分有个时间导致问题，最终跟RK拿到最新的patch让唤醒时间直接加速500MS.

我们在日志下发现问题，并给询问了RK，最终发现这部分代码没有更新到最新的部分。

hi rk:
为什么亮屏的时候有时候会打印这句VOP等待超时？请问下这是什么意思。
[ 1211.293492] rockchip-vop ff930000.vop: wait win close timeout
[ 1211.293514] rockchip-vop ff930000.vop: [drm:vop_crtc_enable] Update mode to 1200*1920, close all win
有时候却不会打印。

[ 1216.423283] rockchip-vop ff930000.vop: [drm:vop_crtc_enable] Update mode to 12001920, close all win [ 1223.899741] rockchip-vop ff930000.vop: [drm:vop_crtc_enable] Update mode to 12001920, close all win
[ 1234.386252] rockchip-vop ff930000.vop: [drm:vop_crtc_enable] Update mode to 1200*1920, close all win

代码如下

--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c@@ -139,6 +139,9 @@ #define to_vop_win(x) container_of(x, struct vop_win, base) #define to_vop_plane_state(x) container_of(x, struct vop_plane_state, base)+/*add by VENDOR_PATCH for seep up the drm vop driver at 2018/1/18 for RK Defect #191554, VENDOR_PATCH PAD100-193*/+#define VENDOR_PATCH+ struct vop_zpos {    int win_id;    int zpos;@@ -868,9 +871,15 @@ static void vop_disable_all_planes(struct vop *vop)    vop_disable_allwin(vop);    vop_cfg_done(vop);+#ifdef VENDOR_PATCH    ret = readx_poll_timeout_atomic(vop_is_allwin_disabled,                    vop, active, active,+                    0, 100 * 1000);+#else+    ret = readx_poll_timeout_atomic(vop_is_allwin_disabled,+                vop, active, active,                    0, 500 * 1000);+#endif    if (ret)        dev_err(vop->dev, "wait win close timeout\n"); }@@ -2215,20 +2224,36 @@ static size_t vop_crtc_bandwidth(struct drm_crtc *crtc,    u16 htotal = adjusted_mode->crtc_htotal;    u16 vdisplay = adjusted_mode->crtc_vdisplay;    int clock = adjusted_mode->crtc_clock;+#ifndef VENDOR_PATCH    struct vop *vop = to_vop(crtc);    const struct vop_data *vop_data = vop->data;+#endif    struct vop_plane_state *vop_plane_state;    struct drm_plane_state *pstate;    struct vop_bandwidth *pbandwidth;    struct drm_plane *plane;    u64 bandwidth;    int i, cnt = 0;+#ifdef VENDOR_PATCH+    int plane_num = 0;+#endif    if (!htotal || !vdisplay)        return 0;+#ifndef VENDOR_PATCH    pbandwidth = kmalloc_array(vop_data->win_size, sizeof(*pbandwidth),                  GFP_KERNEL);+#else+    for_each_plane_in_state(state, plane, pstate, i) {+        if (pstate->crtc != crtc || !pstate->fb)+            continue;+        plane_num++;+    }+    pbandwidth = kmalloc_array(plane_num, sizeof(*pbandwidth),+                 GFP_KERNEL);+#endif+    if (!pbandwidth)        return -ENOMEM;@@ -2421,7 +2446,10 @@ static void vop_crtc_enable(struct drm_crtc *crtc)    rockchip_set_system_status(sys_status);    mutex_lock(&vop->vop_lock);    vop_initial(crtc);-+#ifdef VENDOR_PATCH+    vop_disable_allwin(vop);+    VOP_CTRL_SET(vop, standby, 0);+#endif    VOP_CTRL_SET(vop, dclk_pol, 1);    val = (adjusted_mode->flags & DRM_MODE_FLAG_NHSYNC) ?          0 : BIT(HSYNC_POSITIVE);@@ -2549,8 +2577,9 @@ static void vop_crtc_enable(struct drm_crtc *crtc)    /*     * enable vop, all the register would take effect when vop exit standby     */+#ifndef VENDOR_PATCH    VOP_CTRL_SET(vop, standby, 0);-+#endif    enable_irq(vop->irq);    drm_crtc_vblank_on(crtc);    mutex_unlock(&vop->vop_lock);

休眠唤醒流程图

从网上拷贝了个休眠唤醒的流程图，如果以后有问题需要分析的话，可以跟进这个流程去排查。

总结

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