There's an ongoing effort to remove VLAs[1] from the kernel to eventually
turn on -Wvla. The vla in reg_write_range is based on the length of data
passed. The one use of a non-constant size for this range is bounded by
the size buffer passed to hdmi_infoframe_pack which is a fixed size.
Switch to this upper bound.

[1] https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Laura Abbott <labb...@redhat.com>
---
v2: Switch to make the buffer size more transparent and add a bounds
check.
---
 drivers/gpu/drm/i2c/tda998x_drv.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c 
b/drivers/gpu/drm/i2c/tda998x_drv.c
index 9e67a7b4e3a4..c8b6029b7839 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -466,13 +466,22 @@ reg_read_range(struct tda998x_priv *priv, u16 reg, char 
*buf, int cnt)
        return ret;
 }
 
+#define MAX_WRITE_RANGE_BUF 32
+
 static void
 reg_write_range(struct tda998x_priv *priv, u16 reg, u8 *p, int cnt)
 {
        struct i2c_client *client = priv->hdmi;
-       u8 buf[cnt+1];
+       /* This is the maximum size of the buffer passed in */
+       u8 buf[MAX_WRITE_RANGE_BUF + 1];
        int ret;
 
+       if (cnt > MAX_WRITE_RANGE_BUF) {
+               dev_err(&client->dev, "Fixed write buffer too small (%d)\n",
+                               MAX_WRITE_RANGE_BUF);
+               return;
+       }
+
        buf[0] = REG2ADDR(reg);
        memcpy(&buf[1], p, cnt);
 
@@ -679,7 +688,7 @@ static void
 tda998x_write_if(struct tda998x_priv *priv, u8 bit, u16 addr,
                 union hdmi_infoframe *frame)
 {
-       u8 buf[32];
+       u8 buf[MAX_WRITE_RANGE_BUF];
        ssize_t len;
 
        len = hdmi_infoframe_pack(frame, buf, sizeof(buf));
-- 
2.14.3

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