[U-Boot] [PATCH] w1: fix occasional enumeration failure

[Eugen.Hristev at microchip.com]

On 23.11.2018 11:53, Martin Fuzzey wrote:
> Sometimes enumeration fails (about 1 in 50 times on my custom board).
> 
> The underlying reason is probably electrical but Linux does not have
> the problem.
> 
> Comparing the Linux / u-boot implementations shows that Linux
> retries the error case whereas u-boot aborts early.
> 
> Removing the early abort in u-boot fixes the problem.
> 
> Signed-off-by: Martin Fuzzey <martin.fuzzey at flowbird.group>
> ---
>   drivers/w1/w1-uclass.c | 4 ----
>   1 file changed, 4 deletions(-)
> 
> diff --git a/drivers/w1/w1-uclass.c b/drivers/w1/w1-uclass.c
> index 5544b19..ad86bf6 100644
> --- a/drivers/w1/w1-uclass.c
> +++ b/drivers/w1/w1-uclass.c
> @@ -84,10 +84,6 @@ static int w1_enumerate(struct udevice *bus)
>   			rn |= (tmp64 << i);
>   		}
>   
> -		/* last device or error, aborting here */
> -		if ((triplet_ret & 0x03) == 0x03)
> -			last_device = true;
> -

Hello Martin,

Your fix will basically make U-boot try again the same ID ? What happens 
if we keep getting errors at this triplet, we will be stuck in a loop ?
When are we going to abort searching this ID if we keep getting errors ?

Thanks,
Eugen

>   		if ((triplet_ret & 0x03) != 0x03) {
>   			if (desc_bit == last_zero || last_zero < 0) {
>   				last_device = 1;
>