ov5640 video capture时，vfe_v4l2.ko模块挂掉问题分析
1.问题描述
在r16 tina平台，基于ov5640获取摄像头数据时，vfe_v4l2.ko模块挂掉。
2.配置信息
2.1上层应用设置的像素格式为V4L2_PIX_FMT_YUYV，分辨率为480P。
2.2 lichee/linux-3.4/drivers/media/video/sunxi-vfe/platform_cfg.h
2.3 sys_config.fex
[twi2]
twi_used = 1
twi_scl = port:PE12<3><default><default><default>
twi_sda = port:PE13<3><default><default><default>
[csi0]
vip_used = 1
vip_mode = 0
vip_dev_qty = 1
vip_define_sensor_list = 0
vip_csi_pck = port:PE00<2><default><default><default>
vip_csi_mck = port:PE01<2><default><default><default>
vip_csi_hsync = port:PE02<2><default><default><default>
vip_csi_vsync = port:PE03<2><default><default><default>
vip_csi_d0 = port:PE04<2><default><default><default>
vip_csi_d1 = port:PE05<2><default><default><default>
vip_csi_d2 = port:PE06<2><default><default><default>
vip_csi_d3 = port:PE07<2><default><default><default>
vip_csi_d4 = port:PE08<2><default><default><default>
vip_csi_d5 = port:PE09<2><default><default><default>
vip_csi_d6 = port:PE10<2><default><default><default>
vip_csi_d7 = port:PE11<2><default><default><default>
;vip_csi_sck = port:PE12<2><default><default><default>
;vip_csi_sda = port:PE13<2><default><default><default>
vip_dev0_mname = "ov5640"
vip_dev0_pos = "rear"
vip_dev0_lane = 0
vip_dev0_twi_id = 2
vip_dev0_twi_addr = 0x78
vip_dev0_isp_used = 0
vip_dev0_fmt = 0
vip_dev0_stby_mode = 0
vip_dev0_vflip = 0
vip_dev0_hflip = 0
vip_dev0_iovdd = "axp22_dldo3"
vip_dev0_iovdd_vol = 2800000
vip_dev0_avdd = "axp22_dldo2"
vip_dev0_avdd_vol = 2800000
vip_dev0_dvdd = "axp22_eldo2"
vip_dev0_dvdd_vol = 1800000
vip_dev0_afvdd = ""
vip_dev0_afvdd_vol = 2800000
vip_dev0_power_en =
vip_dev0_reset = port:PE14<1><default><default><0>
vip_dev0_pwdn = port:PE15<1><default><default><1>
vip_dev0_flash_en =
vip_dev0_flash_mode =
vip_dev0_af_pwdn =
- kernel 堆栈分析
vfe_v4l2.ko模块链接基址为：0xbf018000
根据内核堆栈的PC(0xbf0208a0)地址可以定位到模块内的偏移为：0x88a0
8894: ebfffffe bl 0 <printk>
8898: e30b3f9c movw r3, #49052 ; 0xbf9c
889c: e7943003 ldr r3, [r4, r3]
88a0: e59331c4 ldr r3, [r3, #452] ; 0x1c4---这一行
88a4: e5893044 str r3, [r9, #68] ; 0x44
88a8: e5953000 ldr r3, [r5]
88ac: e3530000 cmp r3, #0[ 314.483154]
[ 44.243185] [VFE_DEBUG]00000000
[ 44.243193] [VFE_DEBUG]buffer_queue
[ 44.243198] [VFE_DEBUG]buffer_queue
[ 44.243204] [VFE_DEBUG]buffer_queue
[ 44.243210] [VFE_DEBUG]0111111
[ 44.243218] [VFE_DEBUG]buf ptr=cf107680
[ 44.243224] [VFE_DEBUG]frankhhhhhhhhhhhhhh
[ 44.243231] [VFE_DEBUG]frankiiiiiiiiiiiiiiii addr_org=0x60000093
[ 44.243242] [VFE_DEBUG]frankjjjjjjjjjjjjjjjjjj, dev->isp_3a_result_pt=0fd46000
[ 44.243263] Unable to handle kernel NULL pointer dereference at virtual address 000001c4
关键代码如下:
将vfe_v4l2.ko反汇编，主要汇编代码：
