[media] tc358743: don't use variable length array for I2C writes
authorMauro Carvalho Chehab <mchehab@osg.samsung.com>
Tue, 11 Aug 2015 15:18:30 +0000 (12:18 -0300)
committerMauro Carvalho Chehab <mchehab@osg.samsung.com>
Sun, 16 Aug 2015 15:55:07 +0000 (12:55 -0300)
drivers/media/i2c/tc358743.c:148:19: warning: Variable length array is used.

As the maximum size is 1026, we can't use dynamic var, as it
would otherwise spend 1056 bytes of the stack at i2c_wr() function.

So, allocate a buffer with the allowed maximum size together with
the state var.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: Mats Randgaard <matrandg@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
drivers/media/i2c/tc358743.c

index 2e926317d7e93b4e6c82343bfe19cb586183e3b0..fe42c9a1cb7877209c5aafcd76bc03c78d509de0 100644 (file)
@@ -59,6 +59,9 @@ MODULE_LICENSE("GPL");
 #define EDID_NUM_BLOCKS_MAX 8
 #define EDID_BLOCK_SIZE 128
 
+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE  (EDID_NUM_BLOCKS_MAX * EDID_BLOCK_SIZE + 2)
+
 static const struct v4l2_dv_timings_cap tc358743_timings_cap = {
        .type = V4L2_DV_BT_656_1120,
        /* keep this initialization for compatibility with GCC < 4.4.6 */
@@ -94,6 +97,9 @@ struct tc358743_state {
        /* edid  */
        u8 edid_blocks_written;
 
+       /* used by i2c_wr() */
+       u8 wr_data[MAX_XFER_SIZE];
+
        struct v4l2_dv_timings timings;
        u32 mbus_fmt_code;
 
@@ -143,9 +149,13 @@ static void i2c_wr(struct v4l2_subdev *sd, u16 reg, u8 *values, u32 n)
 {
        struct tc358743_state *state = to_state(sd);
        struct i2c_client *client = state->i2c_client;
+       u8 *data = state->wr_data;
        int err, i;
        struct i2c_msg msg;
-       u8 data[2 + n];
+
+       if ((2 + n) > sizeof(state->wr_data))
+               v4l2_warn(sd, "i2c wr reg=%04x: len=%d is too big!\n",
+                         reg, 2 + n);
 
        msg.addr = client->addr;
        msg.buf = data;
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