Hi Wolfram,
On 12/01/2021 17:41, Wolfram Sang wrote:
> The open coded version differs from the one in the core in one way: the
> buffer will be always copied back, even when the transfer failed. It
> looks like it is expected that the sanity check for a correct CRC and
> header will bail out later.
Nah, it's just a bug. It should have returned and checked the error code,
so your patch does the right thing.
Regards,
Hans
>
> Use the block read from the I2C core and propagate a potential errno
> further to the sanity check.
>
> Signed-off-by: Wolfram Sang <[email protected]>
> ---
>
> Note: we could now make the error checking even stronger by checking if
> the number of received bytes is I2C_SMBUS_BLOCK_MAX. But to avoid
> regressions, I kept the logic as is, i.e. only check for errno.
>
> drivers/media/i2c/adv7511-v4l2.c | 40 +++++++++++---------------------
> 1 file changed, 14 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/media/i2c/adv7511-v4l2.c
> b/drivers/media/i2c/adv7511-v4l2.c
> index a3161d709015..0150f76dc6a6 100644
> --- a/drivers/media/i2c/adv7511-v4l2.c
> +++ b/drivers/media/i2c/adv7511-v4l2.c
> @@ -214,36 +214,24 @@ static inline void adv7511_wr_and_or(struct v4l2_subdev
> *sd, u8 reg, u8 clr_mask
> adv7511_wr(sd, reg, (adv7511_rd(sd, reg) & clr_mask) | val_mask);
> }
>
> -static int adv_smbus_read_i2c_block_data(struct i2c_client *client,
> - u8 command, unsigned length, u8
> *values)
> -{
> - union i2c_smbus_data data;
> - int ret;
> -
> - if (length > I2C_SMBUS_BLOCK_MAX)
> - length = I2C_SMBUS_BLOCK_MAX;
> - data.block[0] = length;
> -
> - ret = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
> - I2C_SMBUS_READ, command,
> - I2C_SMBUS_I2C_BLOCK_DATA, &data);
> - memcpy(values, data.block + 1, length);
> - return ret;
> -}
> -
> -static void adv7511_edid_rd(struct v4l2_subdev *sd, uint16_t len, uint8_t
> *buf)
> +static int adv7511_edid_rd(struct v4l2_subdev *sd, uint16_t len, uint8_t
> *buf)
> {
> struct adv7511_state *state = get_adv7511_state(sd);
> + s32 len;
> int i;
> - int err = 0;
>
> v4l2_dbg(1, debug, sd, "%s:\n", __func__);
>
> - for (i = 0; !err && i < len; i += I2C_SMBUS_BLOCK_MAX)
> - err = adv_smbus_read_i2c_block_data(state->i2c_edid, i,
> + for (i = 0; i < len; i += I2C_SMBUS_BLOCK_MAX) {
> + len = i2c_smbus_read_i2c_block_data(state->i2c_edid, i,
> I2C_SMBUS_BLOCK_MAX, buf +
> i);
> - if (err)
> - v4l2_err(sd, "%s: i2c read error\n", __func__);
> + if (len < 0) {
> + v4l2_err(sd, "%s: i2c read error\n", __func__);
> + return len;
> + }
> + }
> +
> + return 0;
> }
>
> static inline int adv7511_cec_read(struct v4l2_subdev *sd, u8 reg)
> @@ -1668,20 +1656,20 @@ static bool adv7511_check_edid_status(struct
> v4l2_subdev *sd)
> if (edidRdy & MASK_ADV7511_EDID_RDY) {
> int segment = adv7511_rd(sd, 0xc4);
> struct adv7511_edid_detect ed;
> + int err;
>
> if (segment >= EDID_MAX_SEGM) {
> v4l2_err(sd, "edid segment number too big\n");
> return false;
> }
> v4l2_dbg(1, debug, sd, "%s: got segment %d\n", __func__,
> segment);
> - adv7511_edid_rd(sd, 256, &state->edid.data[segment * 256]);
> + err = adv7511_edid_rd(sd, 256, &state->edid.data[segment *
> 256]);
> adv7511_dbg_dump_edid(2, debug, sd, segment,
> &state->edid.data[segment * 256]);
> if (segment == 0) {
> state->edid.blocks = state->edid.data[0x7e] + 1;
> v4l2_dbg(1, debug, sd, "%s: %d blocks in total\n",
> __func__, state->edid.blocks);
> }
> - if (!edid_verify_crc(sd, segment) ||
> - !edid_verify_header(sd, segment)) {
> + if (err < 0 || !edid_verify_crc(sd, segment) ||
> !edid_verify_header(sd, segment)) {
> /* edid crc error, force reread of edid segment */
> v4l2_err(sd, "%s: edid crc or header error\n",
> __func__);
> state->have_monitor = false;
>
