diff mbox

gspca pac7311/pac7302: propagate error to higher level software

Message ID 4AF52CF7.7000200@freemail.hu (mailing list archive)
State Accepted
Headers show

Commit Message

Németh Márton Nov. 7, 2009, 8:16 a.m. UTC
None
diff mbox

Patch

diff -upr a/linux/drivers/media/video/gspca/pac7302.c b/linux/drivers/media/video/gspca/pac7302.c
--- a/linux/drivers/media/video/gspca/pac7302.c	2009-11-07 08:57:26.000000000 +0100
+++ b/linux/drivers/media/video/gspca/pac7302.c	2009-11-07 09:08:16.000000000 +0100
@@ -331,7 +331,7 @@  static const __u8 page3_7302[] = {
 	0x00
 };

-static void reg_w_buf(struct gspca_dev *gspca_dev,
+static int reg_w_buf(struct gspca_dev *gspca_dev,
 		  __u8 index,
 		  const char *buffer, int len)
 {
@@ -349,6 +349,7 @@  static void reg_w_buf(struct gspca_dev *
 		PDEBUG(D_ERR, "reg_w_buf(): "
 		"Failed to write registers to index 0x%x, error %i",
 		index, ret);
+	return ret;
 }

 #if 0 /* not used */
@@ -373,7 +374,7 @@  static __u8 reg_r(struct gspca_dev *gspc
 }
 #endif

-static void reg_w(struct gspca_dev *gspca_dev,
+static int reg_w(struct gspca_dev *gspca_dev,
 		  __u8 index,
 		  __u8 value)
 {
@@ -390,23 +391,27 @@  static void reg_w(struct gspca_dev *gspc
 		PDEBUG(D_ERR, "reg_w(): "
 		"Failed to write register to index 0x%x, value 0x%x, error %i",
 		index, value, ret);
+	return ret;
 }

-static void reg_w_seq(struct gspca_dev *gspca_dev,
+static int reg_w_seq(struct gspca_dev *gspca_dev,
 		const __u8 *seq, int len)
 {
+	int ret = 0;
 	while (--len >= 0) {
-		reg_w(gspca_dev, seq[0], seq[1]);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, seq[0], seq[1]);
 		seq += 2;
 	}
+	return ret;
 }

 /* load the beginning of a page */
-static void reg_w_page(struct gspca_dev *gspca_dev,
+static int reg_w_page(struct gspca_dev *gspca_dev,
 			const __u8 *page, int len)
 {
 	int index;
-	int ret;
+	int ret = 0;

 	for (index = 0; index < len; index++) {
 		if (page[index] == SKIP)		/* skip this index */
@@ -418,52 +423,61 @@  static void reg_w_page(struct gspca_dev
 			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 				0, index, gspca_dev->usb_buf, 1,
 				500);
-		if (ret < 0)
+		if (ret < 0) {
 			PDEBUG(D_ERR, "reg_w_page(): "
 			"Failed to write register to index 0x%x, "
 			"value 0x%x, error %i",
 			index, page[index], ret);
+			break;
+		}
 	}
+	return ret;
 }

 /* output a variable sequence */
-static void reg_w_var(struct gspca_dev *gspca_dev,
+static int reg_w_var(struct gspca_dev *gspca_dev,
 			const __u8 *seq,
 			const __u8 *page3, unsigned int page3_len,
 			const __u8 *page4, unsigned int page4_len)
 {
 	int index, len;
+	int ret = 0;

 	for (;;) {
 		index = *seq++;
 		len = *seq++;
 		switch (len) {
 		case END_OF_SEQUENCE:
-			return;
+			return ret;
 		case LOAD_PAGE4:
-			reg_w_page(gspca_dev, page4, page4_len);
+			ret = reg_w_page(gspca_dev, page4, page4_len);
 			break;
 		case LOAD_PAGE3:
-			reg_w_page(gspca_dev, page3, page3_len);
+			ret = reg_w_page(gspca_dev, page3, page3_len);
 			break;
 		default:
 			if (len > USB_BUF_SZ) {
 				PDEBUG(D_ERR|D_STREAM,
 					"Incorrect variable sequence");
-				return;
+				return -EINVAL;
 			}
 			while (len > 0) {
 				if (len < 8) {
-					reg_w_buf(gspca_dev, index, seq, len);
+					ret = reg_w_buf(gspca_dev,
+						index, seq, len);
+					if (ret < 0)
+						return ret;
 					seq += len;
 					break;
 				}
-				reg_w_buf(gspca_dev, index, seq, 8);
+				ret = reg_w_buf(gspca_dev, index, seq, 8);
 				seq += 8;
 				index += 8;
 				len -= 8;
 			}
 		}
+		if (ret < 0)
+			return ret;
 	}
 	/* not reached */
 }
@@ -493,10 +507,11 @@  static int sd_config(struct gspca_dev *g
 }

 /* This function is used by pac7302 only */
-static void setbrightcont(struct gspca_dev *gspca_dev)
+static int setbrightcont(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
 	int i, v;
+	int ret;
 	static const __u8 max[10] =
 		{0x29, 0x33, 0x42, 0x5a, 0x6e, 0x80, 0x9f, 0xbb,
 		 0xd4, 0xec};
@@ -504,7 +519,7 @@  static void setbrightcont(struct gspca_d
 		{0x35, 0x33, 0x33, 0x2f, 0x2a, 0x25, 0x1e, 0x17,
 		 0x11, 0x0b};

-	reg_w(gspca_dev, 0xff, 0x00);	/* page 0 */
+	ret = reg_w(gspca_dev, 0xff, 0x00);	/* page 0 */
 	for (i = 0; i < 10; i++) {
 		v = max[i];
 		v += (sd->brightness - BRIGHTNESS_MAX)
@@ -514,47 +529,62 @@  static void setbrightcont(struct gspca_d
 			v = 0;
 		else if (v > 0xff)
 			v = 0xff;
-		reg_w(gspca_dev, 0xa2 + i, v);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0xa2 + i, v);
 	}
-	reg_w(gspca_dev, 0xdc, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0xdc, 0x01);
+	return ret;
 }

 /* This function is used by pac7302 only */
-static void setcolors(struct gspca_dev *gspca_dev)
+static int setcolors(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
 	int i, v;
+	int ret;
 	static const int a[9] =
 		{217, -212, 0, -101, 170, -67, -38, -315, 355};
 	static const int b[9] =
 		{19, 106, 0, 19, 106, 1, 19, 106, 1};

-	reg_w(gspca_dev, 0xff, 0x03);	/* page 3 */
-	reg_w(gspca_dev, 0x11, 0x01);
-	reg_w(gspca_dev, 0xff, 0x00);	/* page 0 */
+	ret = reg_w(gspca_dev, 0xff, 0x03);	/* page 3 */
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x11, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0xff, 0x00);	/* page 0 */
 	for (i = 0; i < 9; i++) {
 		v = a[i] * sd->colors / COLOR_MAX + b[i];
-		reg_w(gspca_dev, 0x0f + 2 * i, (v >> 8) & 0x07);
-		reg_w(gspca_dev, 0x0f + 2 * i + 1, v);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0x0f + 2 * i, (v >> 8) & 0x07);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0x0f + 2 * i + 1, v);
 	}
-	reg_w(gspca_dev, 0xdc, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0xdc, 0x01);
 	PDEBUG(D_CONF|D_STREAM, "color: %i", sd->colors);
+	return ret;
 }

-static void setgain(struct gspca_dev *gspca_dev)
+static int setgain(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
+	int ret;

-	reg_w(gspca_dev, 0xff, 0x03);		/* page 3 */
-	reg_w(gspca_dev, 0x10, sd->gain >> 3);
+	ret = reg_w(gspca_dev, 0xff, 0x03);		/* page 3 */
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x10, sd->gain >> 3);

 	/* load registers to sensor (Bit 0, auto clear) */
-	reg_w(gspca_dev, 0x11, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x11, 0x01);
+	return ret;
 }

-static void setexposure(struct gspca_dev *gspca_dev)
+static int setexposure(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
+	int ret;
 	__u8 reg;

 	/* register 2 of frame 3/4 contains the clock divider configuring the
@@ -570,47 +600,58 @@  static void setexposure(struct gspca_dev
 	   the nearest multiple of 3, except when between 6 and 12? */
 	if (reg < 6 || reg > 12)
 		reg = ((reg + 1) / 3) * 3;
-	reg_w(gspca_dev, 0xff, 0x03);		/* page 3 */
-	reg_w(gspca_dev, 0x02, reg);
+	ret = reg_w(gspca_dev, 0xff, 0x03);		/* page 3 */
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x02, reg);

 	/* load registers to sensor (Bit 0, auto clear) */
-	reg_w(gspca_dev, 0x11, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x11, 0x01);
+	return ret;
 }

-static void sethvflip(struct gspca_dev *gspca_dev)
+static int sethvflip(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
+	int ret;
 	__u8 data;

-	reg_w(gspca_dev, 0xff, 0x03);		/* page 3 */
+	ret = reg_w(gspca_dev, 0xff, 0x03);		/* page 3 */
 	data = (sd->hflip ? 0x08 : 0x00) | (sd->vflip ? 0x04 : 0x00);
-	reg_w(gspca_dev, 0x21, data);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x21, data);
 	/* load registers to sensor (Bit 0, auto clear) */
-	reg_w(gspca_dev, 0x11, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x11, 0x01);
+	return ret;
 }

 /* this function is called at probe and resume time for pac7302 */
 static int sd_init(struct gspca_dev *gspca_dev)
 {
-	reg_w_seq(gspca_dev, init_7302, sizeof(init_7302)/2);
-
-	return 0;
+	return reg_w_seq(gspca_dev, init_7302, sizeof(init_7302)/2);
 }

 static int sd_start(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
+	int ret = 0;

 	sd->sof_read = 0;

-	reg_w_var(gspca_dev, start_7302,
+	ret = reg_w_var(gspca_dev, start_7302,
 		page3_7302, sizeof(page3_7302),
 		NULL, 0);
-	setbrightcont(gspca_dev);
-	setcolors(gspca_dev);
-	setgain(gspca_dev);
-	setexposure(gspca_dev);
-	sethvflip(gspca_dev);
+	if (0 <= ret)
+		ret = setbrightcont(gspca_dev);
+	if (0 <= ret)
+		ret = setcolors(gspca_dev);
+	if (0 <= ret)
+		setgain(gspca_dev);
+	if (0 <= ret)
+		setexposure(gspca_dev);
+	if (0 <= ret)
+		sethvflip(gspca_dev);

 	/* only resolution 640x480 is supported for pac7302 */

@@ -619,26 +660,34 @@  static int sd_start(struct gspca_dev *gs
 	atomic_set(&sd->avg_lum, -1);

 	/* start stream */
-	reg_w(gspca_dev, 0xff, 0x01);
-	reg_w(gspca_dev, 0x78, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0xff, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x78, 0x01);

-	return 0;
+	return ret;
 }

 static void sd_stopN(struct gspca_dev *gspca_dev)
 {
+	int ret;
+
 	/* stop stream */
-	reg_w(gspca_dev, 0xff, 0x01);
-	reg_w(gspca_dev, 0x78, 0x00);
+	ret = reg_w(gspca_dev, 0xff, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x78, 0x00);
 }

 /* called on streamoff with alt 0 and on disconnect for pac7302 */
 static void sd_stop0(struct gspca_dev *gspca_dev)
 {
+	int ret;
+
 	if (!gspca_dev->present)
 		return;
-	reg_w(gspca_dev, 0xff, 0x01);
-	reg_w(gspca_dev, 0x78, 0x40);
+	ret = reg_w(gspca_dev, 0xff, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x78, 0x40);
 }

 /* Include pac common sof detection functions */
diff -upr a/linux/drivers/media/video/gspca/pac7311.c b/linux/drivers/media/video/gspca/pac7311.c
--- a/linux/drivers/media/video/gspca/pac7311.c	2009-11-07 07:05:42.000000000 +0100
+++ b/linux/drivers/media/video/gspca/pac7311.c	2009-11-07 09:09:32.000000000 +0100
@@ -259,7 +259,7 @@  static const __u8 page4_7311[] = {
 	0x23, 0x28, 0x04, 0x11, 0x00, 0x00
 };

-static void reg_w_buf(struct gspca_dev *gspca_dev,
+static int reg_w_buf(struct gspca_dev *gspca_dev,
 		  __u8 index,
 		  const char *buffer, int len)
 {
@@ -277,6 +277,7 @@  static void reg_w_buf(struct gspca_dev *
 		PDEBUG(D_ERR, "reg_w_buf(): "
 		"Failed to write registers to index 0x%x, error %i",
 		index, ret);
+	return ret;
 }

 #if 0 /* not used */
@@ -301,7 +302,7 @@  static __u8 reg_r(struct gspca_dev *gspc
 }
 #endif

-static void reg_w(struct gspca_dev *gspca_dev,
+static int reg_w(struct gspca_dev *gspca_dev,
 		  __u8 index,
 		  __u8 value)
 {
@@ -318,23 +319,27 @@  static void reg_w(struct gspca_dev *gspc
 		PDEBUG(D_ERR, "reg_w(): "
 		"Failed to write register to index 0x%x, value 0x%x, error %i",
 		index, value, ret);
+	return ret;
 }

-static void reg_w_seq(struct gspca_dev *gspca_dev,
+static int reg_w_seq(struct gspca_dev *gspca_dev,
 		const __u8 *seq, int len)
 {
+	int ret = 0;
 	while (--len >= 0) {
-		reg_w(gspca_dev, seq[0], seq[1]);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, seq[0], seq[1]);
 		seq += 2;
 	}
+	return ret;
 }

 /* load the beginning of a page */
-static void reg_w_page(struct gspca_dev *gspca_dev,
+static int reg_w_page(struct gspca_dev *gspca_dev,
 			const __u8 *page, int len)
 {
 	int index;
-	int ret;
+	int ret = 0;

 	for (index = 0; index < len; index++) {
 		if (page[index] == SKIP)		/* skip this index */
@@ -346,52 +351,61 @@  static void reg_w_page(struct gspca_dev
 			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 				0, index, gspca_dev->usb_buf, 1,
 				500);
-		if (ret < 0)
+		if (ret < 0) {
 			PDEBUG(D_ERR, "reg_w_page(): "
 			"Failed to write register to index 0x%x, "
 			"value 0x%x, error %i",
 			index, page[index], ret);
+			break;
+		}
 	}
+	return ret;
 }

 /* output a variable sequence */
-static void reg_w_var(struct gspca_dev *gspca_dev,
+static int reg_w_var(struct gspca_dev *gspca_dev,
 			const __u8 *seq,
 			const __u8 *page3, unsigned int page3_len,
 			const __u8 *page4, unsigned int page4_len)
 {
 	int index, len;
+	int ret = 0;

 	for (;;) {
 		index = *seq++;
 		len = *seq++;
 		switch (len) {
 		case END_OF_SEQUENCE:
-			return;
+			return ret;
 		case LOAD_PAGE4:
-			reg_w_page(gspca_dev, page4, page4_len);
+			ret = reg_w_page(gspca_dev, page4, page4_len);
 			break;
 		case LOAD_PAGE3:
-			reg_w_page(gspca_dev, page3, page3_len);
+			ret = reg_w_page(gspca_dev, page3, page3_len);
 			break;
 		default:
 			if (len > USB_BUF_SZ) {
 				PDEBUG(D_ERR|D_STREAM,
 					"Incorrect variable sequence");
-				return;
+				return -EINVAL;
 			}
 			while (len > 0) {
 				if (len < 8) {
-					reg_w_buf(gspca_dev, index, seq, len);
+					ret = reg_w_buf(gspca_dev,
+						index, seq, len);
+					if (ret < 0)
+						return ret;
 					seq += len;
 					break;
 				}
-				reg_w_buf(gspca_dev, index, seq, 8);
+				ret = reg_w_buf(gspca_dev, index, seq, 8);
 				seq += 8;
 				index += 8;
 				len -= 8;
 			}
 		}
+		if (ret < 0)
+			return ret;
 	}
 	/* not reached */
 }
@@ -419,36 +433,46 @@  static int sd_config(struct gspca_dev *g
 }

 /* This function is used by pac7311 only */
-static void setcontrast(struct gspca_dev *gspca_dev)
+static int setcontrast(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
+	int ret;

-	reg_w(gspca_dev, 0xff, 0x04);
-	reg_w(gspca_dev, 0x10, sd->contrast >> 4);
+	ret = reg_w(gspca_dev, 0xff, 0x04);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x10, sd->contrast >> 4);
 	/* load registers to sensor (Bit 0, auto clear) */
-	reg_w(gspca_dev, 0x11, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x11, 0x01);
+	return ret;
 }

-static void setgain(struct gspca_dev *gspca_dev)
+static int setgain(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
 	int gain = GAIN_MAX - sd->gain;
+	int ret;

 	if (gain < 1)
 		gain = 1;
 	else if (gain > 245)
 		gain = 245;
-	reg_w(gspca_dev, 0xff, 0x04);		/* page 4 */
-	reg_w(gspca_dev, 0x0e, 0x00);
-	reg_w(gspca_dev, 0x0f, gain);
+	ret = reg_w(gspca_dev, 0xff, 0x04);		/* page 4 */
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x0e, 0x00);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x0f, gain);

 	/* load registers to sensor (Bit 0, auto clear) */
-	reg_w(gspca_dev, 0x11, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x11, 0x01);
+	return ret;
 }

-static void setexposure(struct gspca_dev *gspca_dev)
+static int setexposure(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
+	int ret;
 	__u8 reg;

 	/* register 2 of frame 3/4 contains the clock divider configuring the
@@ -460,71 +484,94 @@  static void setexposure(struct gspca_dev
 	else if (reg > 63)
 		reg = 63;

-	reg_w(gspca_dev, 0xff, 0x04);		/* page 4 */
-	reg_w(gspca_dev, 0x02, reg);
+	ret = reg_w(gspca_dev, 0xff, 0x04);		/* page 4 */
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x02, reg);
 	/* Page 1 register 8 must always be 0x08 except when not in
 	   640x480 mode and Page3/4 reg 2 <= 3 then it must be 9 */
-	reg_w(gspca_dev, 0xff, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0xff, 0x01);
 	if (gspca_dev->cam.cam_mode[(int)gspca_dev->curr_mode].priv &&
-			reg <= 3)
-		reg_w(gspca_dev, 0x08, 0x09);
-	else
-		reg_w(gspca_dev, 0x08, 0x08);
+			reg <= 3) {
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0x08, 0x09);
+	} else {
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0x08, 0x08);
+	}

 	/* load registers to sensor (Bit 0, auto clear) */
-	reg_w(gspca_dev, 0x11, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x11, 0x01);
+	return ret;
 }

-static void sethvflip(struct gspca_dev *gspca_dev)
+static int sethvflip(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
+	int ret;
 	__u8 data;

-	reg_w(gspca_dev, 0xff, 0x04);		/* page 4 */
+	ret = reg_w(gspca_dev, 0xff, 0x04);		/* page 4 */
 	data = (sd->hflip ? 0x04 : 0x00) | (sd->vflip ? 0x08 : 0x00);
-	reg_w(gspca_dev, 0x21, data);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x21, data);
 	/* load registers to sensor (Bit 0, auto clear) */
-	reg_w(gspca_dev, 0x11, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x11, 0x01);
+	return ret;
 }

 /* this function is called at probe and resume time for pac7311 */
 static int sd_init(struct gspca_dev *gspca_dev)
 {
-	reg_w_seq(gspca_dev, init_7311, sizeof(init_7311)/2);
-
-	return 0;
+	return reg_w_seq(gspca_dev, init_7311, sizeof(init_7311)/2);
 }

 static int sd_start(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
+	int ret;

 	sd->sof_read = 0;

-	reg_w_var(gspca_dev, start_7311,
+	ret = reg_w_var(gspca_dev, start_7311,
 		NULL, 0,
 		page4_7311, sizeof(page4_7311));
-	setcontrast(gspca_dev);
-	setgain(gspca_dev);
-	setexposure(gspca_dev);
-	sethvflip(gspca_dev);
+	if (0 <= ret)
+		ret = setcontrast(gspca_dev);
+	if (0 <= ret)
+		ret = setgain(gspca_dev);
+	if (0 <= ret)
+		ret = setexposure(gspca_dev);
+	if (0 <= ret)
+		ret = sethvflip(gspca_dev);

 	/* set correct resolution */
 	switch (gspca_dev->cam.cam_mode[(int) gspca_dev->curr_mode].priv) {
 	case 2:					/* 160x120 pac7311 */
-		reg_w(gspca_dev, 0xff, 0x01);
-		reg_w(gspca_dev, 0x17, 0x20);
-		reg_w(gspca_dev, 0x87, 0x10);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0xff, 0x01);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0x17, 0x20);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0x87, 0x10);
 		break;
 	case 1:					/* 320x240 pac7311 */
-		reg_w(gspca_dev, 0xff, 0x01);
-		reg_w(gspca_dev, 0x17, 0x30);
-		reg_w(gspca_dev, 0x87, 0x11);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0xff, 0x01);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0x17, 0x30);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0x87, 0x11);
 		break;
 	case 0:					/* 640x480 */
-		reg_w(gspca_dev, 0xff, 0x01);
-		reg_w(gspca_dev, 0x17, 0x00);
-		reg_w(gspca_dev, 0x87, 0x12);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0xff, 0x01);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0x17, 0x00);
+		if (0 <= ret)
+			ret = reg_w(gspca_dev, 0x87, 0x12);
 		break;
 	}

@@ -533,10 +580,12 @@  static int sd_start(struct gspca_dev *gs
 	atomic_set(&sd->avg_lum, -1);

 	/* start stream */
-	reg_w(gspca_dev, 0xff, 0x01);
-	reg_w(gspca_dev, 0x78, 0x05);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0xff, 0x01);
+	if (0 <= ret)
+		ret = reg_w(gspca_dev, 0x78, 0x05);

-	return 0;
+	return ret;
 }

 static void sd_stopN(struct gspca_dev *gspca_dev)