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请教一个printk的简单问题 [复制链接]

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21 [报告]
发表于 2011-05-09 16:45 |只看该作者
回复 18# amarant


    #include <linux/i2c.h>
#include <linux/videodev2.h>
#include <linux/delay.h>
#include <asm/div64.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <media/v4l2-common.h>
#include <media/v4l2-device.h>
#include "mt9p031.h"
#include <media/v4l2-i2c-drv.h>
#include <media/v4l2-chip-ident.h>



MODULE_LICENSE("GPL";

/* Debug functions */
static int debug;
module_param(debug, bool, 0644);
MODULE_PARM_DESC(debug, "Debug level (0-1)";
MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>";
MODULE_DESCRIPTION("Micron mt9p031 sensor driver";
MODULE_LICENSE("GPL";


/* supported controls */
static struct v4l2_queryctrl mt9p031_qctrl[] = {                   /***/
        {
                .id = V4L2_CID_GAIN,
                .type = V4L2_CTRL_TYPE_INTEGER,
                .name = "Gain",
                .minimum = 0,
                .maximum = (1 << 10) - 1,  /*0到111111111*/
                .step = 1,
                .default_value = 0x0020,
                .flags = 0,
        }, {
                .id = V4L2_CID_RED_BALANCE,
                .type = V4L2_CTRL_TYPE_INTEGER,
                .name = "Red Balance",
                .minimum = -1 << 9,
                .maximum = (1 << 9) - 1,
                .step = 1,
                .default_value = 0,
                .flags = 0,
        }, {
                .id = V4L2_CID_BLUE_BALANCE,
                .type = V4L2_CTRL_TYPE_INTEGER,
                .name = "Blue Balance",
                .minimum = -1 << 9,
                .maximum = (1 << 9) - 1,
                .step = 1,
                .default_value = 0,
                .flags = 0,
        }, {
                .id      = V4L2_CID_HFLIP,
                .type    = V4L2_CTRL_TYPE_BOOLEAN,
                .name    = "Mirror",
                .minimum = 0,
                .maximum = 1,
                .step    = 1,
                .default_value = 0,
                .flags = 0,
        }, {
                .id      = V4L2_CID_VFLIP,
                .type    = V4L2_CTRL_TYPE_BOOLEAN,
                .name    = "Vflip",
                .minimum = 0,
                .maximum = 1,
                .step    = 1,
                .default_value = 0,
                .flags = 0,
        }, {
        }
};

struct mt9p031 {
        struct v4l2_subdev sd;
        unsigned width, height;
        unsigned xtal;                                    
        unsigned hflip:1;
        unsigned vflip:1;

        u16 global_gain, red_bal, blue_bal;
};

static inline struct mt9p031 *to_mt9p031(struct v4l2_subdev *sd)
{
        return container_of(sd, struct mt9p031, sd);   
}

static int mt9p031_read(struct v4l2_subdev *sd, unsigned char addr)
{
        struct i2c_client *c = v4l2_get_subdevdata(sd);
        __be16 buffer;
        int rc, val;
        //c->adapter = 2;
        v4l2_dbg(0, debug, sd,
                         "ccccccccccccccccccccccccccccccccccccccccccccccccccccccccc == %d (aaaaaaaaaaaaa)\n", val);
        rc = i2c_master_send(c, &addr, 1);
        if (rc != 1)
                v4l2_dbg(0, debug, sd,
                         "i2c i/o error: rc == %d (should be 1)\n", rc);
       
        printk(KERN_EMERG " the i2c_client ad is %d \n",c->adapter);

        msleep(10);                         /**/
       

        rc = i2c_master_recv(c, (char *)&buffer, 2);
        if (rc != 2)
                v4l2_dbg(0, debug, sd,
                         "i2c i/o error: rc == %d (should be 2)\n", rc);

        val = be16_to_cpu(buffer);

        v4l2_dbg(2, debug, sd, "mt9p031: read 0x%02x = 0x%04x\n", addr, val);

        return val;
        printk(KERN_EMERG  "this zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzis the mt9p031 driver2 \n";
}

static void mt9p031_write(struct v4l2_subdev *sd, unsigned char addr,
                                 u16 value)
{
        struct i2c_client *c = v4l2_get_subdevdata(sd);
        //c->adapter = 2;
        unsigned char buffer[3];
        int rc;

        buffer[0] = addr;
        buffer[1] = value >> 8;
        buffer[2] = value & 0xff;

        v4l2_dbg(2, debug, sd,
                 "mt9p031: writing 0x%02x 0x%04x\n", buffer[0], value);
       
        rc = i2c_master_send(c, buffer, 3);
        if (rc != 3)
                v4l2_dbg(0, debug, sd,
                         "i2c i/o error: rc == %d (should be 3)\n", rc);
       printk(KERN_DEBUG "this is the mt9p031 driver3 \n";
}


struct i2c_reg_value {
        unsigned char reg;
        u16           value;
};

/*
* Values used at the original driver
* Some values are marked as Reserved at the datasheet
*/
static const struct i2c_reg_value mt9p031_init_default[] = {
                { R00D_MT9P031_RESET,0x0000 },
                { R00D_MT9P031_RESET,0x0001 },

                { R00C_MT9P031_SHUTTER_DELAY,0x0000 },
                { R008_MT9P031_SHUTTER_WIDTH_UPPER,0x0000},
              {R009_MT9P031_SHUTTER_WIDTH_LOWER,0x0797 },

                {R005_MT9P031_HBLANK,0x1C1},        // hblank 450

                { R00A_MT9P031_PIXEL_CLK_CTRL,0x8000 },        //invert pixclk ,capture on rising edge

                { R007_MT9P031_OUT_CTRL        ,0x1f82 },        /* chip enable */
};


static void set_balance(struct v4l2_subdev *sd)
{
        struct mt9p031 *core = to_mt9p031(sd);
        u16 green1_gain, green2_gain, blue_gain, red_gain;

        green1_gain = core->global_gain;
        green2_gain = core->global_gain;

        blue_gain = core->global_gain +
                    core->global_gain * core->blue_bal / (1 << 9);

        red_gain = core->global_gain +
                   core->global_gain * core->red_bal / (1 << 9);

        mt9p031_write(sd, R02B_MT9P031_GREEN_1_GAIN, green1_gain);
        mt9p031_write(sd, R02E_MT9P031_GREEN_2_GAIN,  green1_gain);
        mt9p031_write(sd, R02C_MT9P031_BLUE_GAIN, blue_gain);
        mt9p031_write(sd, R02D_MT9P031_RED_GAIN, red_gain);
}

static void calc_fps(struct v4l2_subdev *sd, u32 *numerator, u32 *denominator)
{
        struct mt9p031 *core = to_mt9p031(sd);
        unsigned height, width, hblank, vblank, speed;
        unsigned row_time, t_time;
        u64 frames_per_ms;
        unsigned tmp;

        height = mt9p031_read(sd, R003_MT9P031_HEIGHT);
        width = mt9p031_read(sd, R004_MT9P031_WIDTH);
        hblank = mt9p031_read(sd,R005_MT9P031_HBLANK);
        vblank = mt9p031_read(sd, R006_MT9P031_VBLANK);
        speed = mt9p031_read(sd, R00A_MT9P031_PIXEL_CLK_CTRL);

        row_time = (width + 140 + hblank) * (speed + 2);
        t_time = row_time * (height + vblank + 1);

        frames_per_ms = core->xtal * 1000l;         
        do_div(frames_per_ms, t_time);
        tmp = frames_per_ms;

        v4l2_dbg(1, debug, sd, "rogrammed to %u.%03u fps (%d pixel clcks)\n",
                tmp / 1000, tmp % 1000, t_time);             /*?*/

        if (numerator && denominator) {         
                *numerator = 1000;
                *denominator = (u32)frames_per_ms;
        printk(KERN_DEBUG "the frames_per_ms value is %p \n",denominator);
}
}

static u16 calc_speed(struct v4l2_subdev *sd, u32 numerator, u32 denominator)
{
        struct mt9p031 *core = to_mt9p031(sd);
        unsigned height, width, hblank, vblank;
        unsigned row_time, line_time;
        u64 t_time, speed;

        /* Avoid bogus calculus */
        if (!numerator || !denominator)
                return 0;

        height = mt9p031_read(sd, R003_MT9P031_HEIGHT);
        width = mt9p031_read(sd, R004_MT9P031_WIDTH);
        hblank = mt9p031_read(sd, R005_MT9P031_HBLANK);
        vblank = mt9p031_read(sd, R006_MT9P031_VBLANK);

        row_time = width + 113 + hblank;
        line_time = height + vblank + 1;

        t_time = core->xtal * ((u64)numerator);
        /* round to the closest value */
        t_time += denominator / 2;
        do_div(t_time, denominator);

        speed = t_time;
        do_div(speed, row_time * line_time);

        /* Avoid having a negative value for speed */
        if (speed < 2)
                speed = 0;
        else
                speed -= 2;

        /* Avoid speed overflow */
        if (speed > 15)
                return 15;

        return (u16)speed;
        printk(KERN_DEBUG "this is the mt9p031_read driver5 speed value %d \n",speed);
}

static void set_res(struct v4l2_subdev *sd)
{
        struct mt9p031 *core = to_mt9p031(sd);
        unsigned vstart, hstart;

        /*
         * The mt9p031 doesn't have scaling. So, in order to select the desired
         * resolution, we're cropping at the middle of the sensor.
         * hblank and vblank should be adjusted, in order to warrant that
         * we'll preserve the line timings for 30 fps, no matter what resolution
         * is selected.
         * NOTE: datasheet says that width (and height) should be filled with
         * width-1. However, this doesn't work, since one pixel per line will
         * be missing.
         */

        hstart = 54 + (2592 - core->width) / 2;
        mt9p031_write(sd,R002_MT9P031_COLSTART, hstart);
        mt9p031_write(sd, R004_MT9P031_WIDTH, core->width);
        mt9p031_write(sd, R005_MT9P031_HBLANK, 1521 - core->width);

        vstart = 16 + (1944 - core->height) / 2;
        mt9p031_write(sd, R001_MT9P031_ROWSTART, vstart);
        mt9p031_write(sd, R003_MT9P031_HEIGHT, core->height);
        mt9p031_write(sd, R006_MT9P031_VBLANK, 985 - core->height);

        calc_fps(sd, NULL, NULL);
      printk(KERN_DEBUG "this is the mt9p031_read driver6 \n";
};

static void set_read_mode(struct v4l2_subdev *sd)
{
        struct mt9p031 *core = to_mt9p031(sd);
        unsigned mode = 0x1000;

        if (core->hflip)
                mode |= 0x8000;

        if (core->vflip)
                mode |= 0x4000;

        mt9p031_write(sd, R020_MT9P031_READ_MODE2, mode);
printk(KERN_DEBUG "this is the mt9p031_read driver7 \n";
}

static int mt9p031_reset(struct v4l2_subdev *sd, u32 val)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(mt9p031_init_default); i++)
                mt9p031_write(sd, mt9p031_init_default.reg,
                               mt9p031_init_default.value);

        set_balance(sd);
        set_res(sd);
        set_read_mode(sd);

        return 0;
};

static int mt9p031_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl)
{
        struct mt9p031 *core = to_mt9p031(sd);

        v4l2_dbg(1, debug, sd, "g_ctrl called\n";

        switch (ctrl->id) {
        case V4L2_CID_GAIN:
                ctrl->value = core->global_gain;
                return 0;
        case V4L2_CID_RED_BALANCE:
                ctrl->value = core->red_bal;
                return 0;
        case V4L2_CID_BLUE_BALANCE:
                ctrl->value = core->blue_bal;
                return 0;
        case V4L2_CID_HFLIP:
                ctrl->value = core->hflip ? 1 : 0;
                return 0;
        case V4L2_CID_VFLIP:
                ctrl->value = core->vflip ? 1 : 0;
                return 0;
        }
        return -EINVAL;
}

static int mt9p031_queryctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc)
{
        int i;

        v4l2_dbg(1, debug, sd, "queryctrl called\n");

        for (i = 0; i < ARRAY_SIZE(mt9p031_qctrl); i++)
                if (qc->id && qc->id == mt9p031_qctrl.id) {
                        memcpy(qc, &(mt9p031_qctrl),
                               sizeof(*qc));
                        return 0;
                }
        printk(KERN_DEBUG "the length of qc is %p",qc);

        return -EINVAL;
      
}


static int mt9p031_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl)
{
        struct mt9p031 *core = to_mt9p031(sd);
        u8 i, n;
        n = ARRAY_SIZE(mt9p031_qctrl);

        for (i = 0; i < n; i++) {
                if (ctrl->id != mt9p031_qctrl.id)
                        continue;
                if (ctrl->value < mt9p031_qctrl.minimum ||
                    ctrl->value > mt9p031_qctrl.maximum)
                        return -ERANGE;
                v4l2_dbg(1, debug, sd, "s_ctrl: id=%d, value=%d\n",
                                        ctrl->id, ctrl->value);
                break;
        }

        switch (ctrl->id) {
        case V4L2_CID_GAIN:
                core->global_gain = ctrl->value;
                break;
        case V4L2_CID_RED_BALANCE:
                core->red_bal = ctrl->value;
                break;
        case V4L2_CID_BLUE_BALANCE:
                core->blue_bal = ctrl->value;
                break;
        case V4L2_CID_HFLIP:
                core->hflip = ctrl->value;
                set_read_mode(sd);
                return 0;
        case V4L2_CID_VFLIP:
                core->vflip = ctrl->value;
                set_read_mode(sd);
                return 0;
        default:
                return -EINVAL;
        }

        set_balance(sd);

        return 0;
        printk(KERN_DEBUG "this is the mt9p031_read driver9 \n");
}

/*huo qu shipi zhichi geshi*/
static int mt9p031_enum_fmt(struct v4l2_subdev *sd, struct v4l2_fmtdesc *fmt)
{
        if (fmt->index > 0)
                return -EINVAL;

        fmt->flags = 0;
        strcpy(fmt->description, "8 bpp Bayer GRGR..BGBG");
        fmt->pixelformat = V4L2_PIX_FMT_SGRBG8;

        return 0;
printk(KERN_DEBUG "this is the mt9p031_read driver10 \n");
}

/*yanzheng qu dong xian shi geshi*/
static int mt9p031_try_fmt(struct v4l2_subdev *sd, struct v4l2_format *fmt)
{
        struct v4l2_pix_format *pix = &fmt->fmt.pix;

        if (pix->pixelformat != V4L2_PIX_FMT_SGRBG
                return -EINVAL;

        v4l_bound_align_image(&pix->width, 640, 2592, 1,
                              &pix->height, 480, 1944, 1, 0);

        return 0;
printk(KERN_DEBUG "this is the mt9p031_read driver11 \n");
}


static int mt9p031_g_parm(struct v4l2_subdev *sd, struct v4l2_streamparm *parms)
{
        struct v4l2_captureparm *cp = &parms->parm.capture;

        if (parms->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;

        memset(cp, 0, sizeof(struct v4l2_captureparm));
        cp->capability = V4L2_CAP_TIMEPERFRAME;
        calc_fps(sd,
                 &cp->timeperframe.numerator,
                 &cp->timeperframe.denominator);

        return 0;
printk(KERN_DEBUG "this is the mt9p031_read driver12 \n");
}

static int mt9p031_s_parm(struct v4l2_subdev *sd, struct v4l2_streamparm *parms)
{
        struct v4l2_captureparm *cp = &parms->parm.capture;
        struct v4l2_fract *tpf = &cp->timeperframe;
        u16 speed;

        if (parms->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
                return -EINVAL;
        if (cp->extendedmode != 0)
                return -EINVAL;

        speed = calc_speed(sd, tpf->numerator, tpf->denominator);
        speed = speed & 0x003f + mt9p031_read(sd,R00A_MT9P031_PIXEL_CLK_CTRL) & 0xffc0;
        mt9p031_write(sd, R00A_MT9P031_PIXEL_CLK_CTRL, speed);
        v4l2_dbg(1, debug, sd, "Setting speed to %d\n", speed);

        /* Recalculate and update fps info */
        calc_fps(sd, &tpf->numerator, &tpf->denominator);

        return 0;
printk(KERN_DEBUG "this is the mt9p031_read driver13 \n");
}


/*shezhi pin puhuo geshi*/
static int mt9p031_s_fmt(struct v4l2_subdev *sd, struct v4l2_format *fmt)
{
        struct v4l2_pix_format *pix = &fmt->fmt.pix;
        struct mt9p031 *core = to_mt9p031(sd);
        int rc;

        rc = mt9p031_try_fmt(sd, fmt);
        if (rc < 0)
                return -EINVAL;

        core->width = pix->width;
        core->height = pix->height;

        set_res(sd);

        return 0;
printk(KERN_DEBUG "this is the mt9p031_read driver14 \n");
}

static int mt9p031_s_config(struct v4l2_subdev *sd, int dumb, void *data)
{
        struct mt9p031 *core = to_mt9p031(sd);
        unsigned *xtal = data;

        v4l2_dbg(1, debug, sd, "s_config called\n");

        if (xtal) {
                core->xtal = *xtal;
                v4l2_dbg(1, debug, sd, "xtal set to %d.%03d MHz\n",
                         *xtal / 1000000, (*xtal / 1000) % 1000);
        }

        return 0;
printk(KERN_DEBUG "this is the mt9p031_read driver14 \n");
}


#ifdef CONFIG_VIDEO_ADV_DEBUG
static int mt9p031_g_register(struct v4l2_subdev *sd,
                              struct v4l2_dbg_register *reg)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);

        if (!v4l2_chip_match_i2c_client(client, &reg->match))
                return -EINVAL;
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        reg->val = mt9p031_read(sd, reg->reg & 0xff);
        reg->size = 2;

        return 0;
printk(KERN_DEBUG "this is the mt9p031_read driver15 \n");
}

static int mt9p031_s_register(struct v4l2_subdev *sd,
                              struct v4l2_dbg_register *reg)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);

        if (!v4l2_chip_match_i2c_client(client, &reg->match))
                return -EINVAL;
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        mt9p031_write(sd, reg->reg & 0xff, reg->val & 0xffff);
printk(KERN_DEBUG "this is the mt9p031_read driver16 \n");
        return 0;

}
#endif

static int mt9p031_g_chip_ident(struct v4l2_subdev *sd,
                                struct v4l2_dbg_chip_ident *chip)
{
        u16 version;
        struct i2c_client *client = v4l2_get_subdevdata(sd);

        version = mt9p031_read(sd, R000_MT9P031_CHIP_VERSION);

        return v4l2_chip_ident_i2c_client(client, chip, V4L2_IDENT_MT9P031,
                                          version);
}

static const struct v4l2_subdev_core_ops mt9p031_core_ops = {
        .queryctrl = mt9p031_queryctrl,
        .g_ctrl = mt9p031_g_ctrl,
        .s_ctrl = mt9p031_s_ctrl,
        .reset = mt9p031_reset,
        .s_config = mt9p031_s_config,
        .g_chip_ident = mt9p031_g_chip_ident,
#ifdef CONFIG_VIDEO_ADV_DEBUG
        .g_register = mt9p031_g_register,
        .s_register = mt9p031_s_register,

#endif
};

static const struct v4l2_subdev_video_ops mt9p031_video_ops = {
        .enum_fmt = mt9p031_enum_fmt,
        .try_fmt = mt9p031_try_fmt,
        .s_fmt = mt9p031_s_fmt,
        .g_parm = mt9p031_g_parm,
        .s_parm = mt9p031_s_parm,
};

static const struct v4l2_subdev_ops mt9p031_ops = {
        .core  = &mt9p031_core_ops,
        .video = &mt9p031_video_ops,
};


/****************************************************************************
                        I2C Client & Driver
****************************************************************************/

static int mt9p031_probe(struct i2c_client *c,
                         const struct i2c_device_id *id)
{
        u16 version;
        struct mt9p031 *core;
        struct v4l2_subdev *sd;

        /* Check if the adapter supports the needed features */
        if (!i2c_check_functionality(c->adapter,
             I2C_FUNC_SMBUS_READ_BYTE | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
                return -EIO;

        core = kzalloc(sizeof(struct mt9p031), GFP_KERNEL);
        if (!core)
                return -ENOMEM;

        sd = &core->sd;
        v4l2_i2c_subdev_init(sd, c, &mt9p031_ops);

        /* Check if the sensor is really a mt9p031 */
        version = mt9p031_read(sd, R000_MT9P031_CHIP_VERSION);
        if (version !=  MT9P031_VERSION)
                {
                v4l2_info(sd, "*** unknown micron chip detected (0x%04x).\n",
                          version);
                printk(KERN_DEBUG "this is the mt9p031 driver17  0x%04x    \n");
                kfree(core);
                return -EINVAL;
       
                }

        core->global_gain = 0x08;          /*????????????*/
        core->width  = 2591;
        core->height = 1943;
        core->xtal = 26000000;        /* Hz */

        v4l_info(c, "micron chip found @ 0x%02x (%s - chip version 0x%04x)\n",
                 c->addr << 1, c->adapter->name, version);

        return 0;
          printk(KERN_DEBUG "this is the mt9p031 driver19 \n");
}

static int mt9p031_remove(struct i2c_client *c)
{
        struct v4l2_subdev *sd = i2c_get_clientdata(c);

        v4l2_dbg(1, debug, sd,
                "mt9p03.c: removing mt9p031 adapter on address 0x%x\n",
                c->addr << 1);

        v4l2_device_unregister_subdev(sd);
        kfree(to_mt9p031(sd));
printk(KERN_DEBUG "this is the mt9p031 driver20 \n");
        return 0;
}

/* ----------------------------------------------------------------------- */

static const struct i2c_device_id mt9p031_id[] = {
        { "mt9p031", 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, mt9p031_id);

static struct v4l2_i2c_driver_data v4l2_i2c_data = {
        .name = "mt9p031",
        .probe = mt9p031_probe,
        .remove = mt9p031_remove,
        .id_table = mt9p031_id,

};

这是我整个程序的完整版,非常感谢!

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日期:2016-11-09 13:19:1015-16赛季CBA联赛之同曦
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22 [报告]
发表于 2011-05-09 16:50 |只看该作者
你这都return了,肯定不能打印了
        return val;
        printk(KERN_EMERG  "this zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzis the mt9p031 driver2 \n";

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日期:2014-08-15 14:32:0015-16赛季CBA联赛之同曦
日期:2017-12-14 15:28:14黑曼巴
日期:2017-08-10 08:14:342017金鸡报晓
日期:2017-02-08 10:39:42黑曼巴
日期:2016-11-15 15:48:38CU十四周年纪念徽章
日期:2016-11-09 13:19:1015-16赛季CBA联赛之同曦
日期:2016-04-08 18:00:03平安夜徽章
日期:2015-12-26 00:06:30程序设计版块每日发帖之星
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日期:2015-07-03 08:39:42
23 [报告]
发表于 2011-05-09 16:51 |只看该作者
执行return以后的函数就返回了   剩下的就不会执行了。C基础哦

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24 [报告]
发表于 2011-05-10 16:57 |只看该作者
回复 23# amarant


    呵呵,大侠说的对哦,俺c基础确实比较薄弱,那我所有的打印信息一个都没显示,不能都是这个原因啊?

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日期:2014-08-15 14:32:0015-16赛季CBA联赛之同曦
日期:2017-12-14 15:28:14黑曼巴
日期:2017-08-10 08:14:342017金鸡报晓
日期:2017-02-08 10:39:42黑曼巴
日期:2016-11-15 15:48:38CU十四周年纪念徽章
日期:2016-11-09 13:19:1015-16赛季CBA联赛之同曦
日期:2016-04-08 18:00:03平安夜徽章
日期:2015-12-26 00:06:30程序设计版块每日发帖之星
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日期:2015-07-03 08:39:42
25 [报告]
发表于 2011-05-10 16:58 |只看该作者
回复 24# mch_kot


    對的。你把打印消息放在return前面

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26 [报告]
发表于 2011-05-10 17:04 |只看该作者
回复 25# amarant


    好,我明白了,不过我的意思是我还有很多printk前后都没有return 的,或者printk放在return前面的,为什么也都没有打印信息呢?是我哪里出了问题?

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日期:2014-08-15 14:32:0015-16赛季CBA联赛之同曦
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日期:2017-08-10 08:14:342017金鸡报晓
日期:2017-02-08 10:39:42黑曼巴
日期:2016-11-15 15:48:38CU十四周年纪念徽章
日期:2016-11-09 13:19:1015-16赛季CBA联赛之同曦
日期:2016-04-08 18:00:03平安夜徽章
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日期:2015-07-03 08:39:42
27 [报告]
发表于 2011-05-10 17:20 |只看该作者
回复 26# mch_kot


    那可能是你的函數沒跑吧。我也沒有仔細分析你的代碼。我先回去吃飯了。你自己檢查下,有時間看看c語言基礎

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28 [报告]
发表于 2011-05-11 09:00 |只看该作者
回复 27# amarant


    你有qq吗?我能否加你?

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22
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日期:2014-08-15 14:32:0015-16赛季CBA联赛之同曦
日期:2017-12-14 15:28:14黑曼巴
日期:2017-08-10 08:14:342017金鸡报晓
日期:2017-02-08 10:39:42黑曼巴
日期:2016-11-15 15:48:38CU十四周年纪念徽章
日期:2016-11-09 13:19:1015-16赛季CBA联赛之同曦
日期:2016-04-08 18:00:03平安夜徽章
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日期:2015-07-03 08:39:42
29 [报告]
发表于 2011-05-11 09:40 |只看该作者
回复 28# mch_kot


    QQ也不經常上,在公司不方便。有什麼問題在論壇上討論不是更好嗎

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30 [报告]
发表于 2011-05-11 22:07 |只看该作者
可以在终端中输入如下命令:echo 7 > /proc/sys/kernel/printk
就可以在终端看到打印信息了。可以参考如下说明
http://hi.baidu.com/singser/blog ... 8e4b3597ddd8d4.html
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