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.

Use the block read from the I2C core and propagate a potential errno
further to the sanity check.

Signed-off-by: Wolfram Sang <wsa+rene...@sang-engineering.com>
---

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;
-- 
2.29.2

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