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[media] saa7115: Don't use a dynamic array 

At least on s390, gcc complains about that:
    drivers/media/i2c/saa7115.c: In function 'saa711x_detect_chip.constprop.2':
    drivers/media/i2c/saa7115.c:1647:1: warning: 'saa711x_detect_chip.constprop.2' uses dynamic stack allocation [enabled by default]

While for me the above report seems utterly bogus, as the
compiler should be optimizing saa711x_detect_chip, merging
it with saa711x_detect_chip and changing:
	char chip_ver[size - 1];
to
	char chip_ver[16];

because this function is only called on this code snippet:
	char name[17];
	...
	ident = saa711x_detect_chip(client, id, name, sizeof(name));

It seems that gcc is not optimizing it, at least on s390.

As getting rid of it is easy, let's do it.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Mauro Carvalho Chehab 2013-05-21 11:36:30 -03:00
parent 2a848b2c7f
commit 6a084d6b3d
1 changed files with 10 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/media/i2c/saa7115.c
View File

@ -1602,6 +1602,8 @@ static const struct v4l2_subdev_ops saa711x_ops = {
.vbi = &saa711x_vbi_ops,
};
#define CHIP_VER_SIZE 16
/* ----------------------------------------------------------------------- */
/**
@ -1609,7 +1611,6 @@ static const struct v4l2_subdev_ops saa711x_ops = {
* @client: I2C client structure.
* @id: I2C device ID structure.
* @name: Name of the device to be filled.
* @size: Size of the name var.
*
* Detects the Philips/NXP saa711x chip, or some clone of it.
* if 'id' is NULL or id->driver_data is equal to 1, it auto-probes
@ -1621,9 +1622,9 @@ static const struct v4l2_subdev_ops saa711x_ops = {
*/
static int saa711x_detect_chip(struct i2c_client *client,
const struct i2c_device_id *id,
char *name, unsigned size)
char *name)
{
char chip_ver[size - 1];
char chip_ver[CHIP_VER_SIZE];
char chip_id;
int i;
int autodetect;
@ -1631,7 +1632,7 @@ static int saa711x_detect_chip(struct i2c_client *client,
autodetect = !id || id->driver_data == 1;
/* Read the chip version register */
for (i = 0; i < size - 1; i++) {
for (i = 0; i < CHIP_VER_SIZE; i++) {
i2c_smbus_write_byte_data(client, 0, i);
chip_ver[i] = i2c_smbus_read_byte_data(client, 0);
name[i] = (chip_ver[i] & 0x0f) + '0';
@ -1643,7 +1644,7 @@ static int saa711x_detect_chip(struct i2c_client *client,
/* Check if it is a Philips/NXP chip */
if (!memcmp(name + 1, "f711", 4)) {
chip_id = name[5];
snprintf(name, size, "saa711%c", chip_id);
snprintf(name, CHIP_VER_SIZE, "saa711%c", chip_id);
if (!autodetect && strcmp(name, id->name))
return -EINVAL;
@ -1651,7 +1652,7 @@ static int saa711x_detect_chip(struct i2c_client *client,
switch (chip_id) {
case '1':
if (chip_ver[0] & 0xf0) {
snprintf(name, size, "saa711%ca", chip_id);
snprintf(name, CHIP_VER_SIZE, "saa711%ca", chip_id);
v4l_info(client, "saa7111a variant found\n");
return V4L2_IDENT_SAA7111A;
}
@ -1689,7 +1690,7 @@ static int saa711x_detect_chip(struct i2c_client *client,
* the lower nibble is a gm7113c.
*/
strlcpy(name, "gm7113c", size);
strlcpy(name, "gm7113c", CHIP_VER_SIZE);
if (!autodetect && strcmp(name, id->name))
return -EINVAL;
@ -1714,13 +1715,13 @@ static int saa711x_probe(struct i2c_client *client,
struct v4l2_subdev *sd;
struct v4l2_ctrl_handler *hdl;
int ident;
char name[17];
char name[CHIP_VER_SIZE + 1];
/* Check if the adapter supports the needed features */
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -EIO;
ident = saa711x_detect_chip(client, id, name, sizeof(name));
ident = saa711x_detect_chip(client, id, name);
if (ident == -EINVAL) {
/* Chip exists, but doesn't match */
v4l_warn(client, "found %s while %s was expected\n",