Re: [PATCH v2 2/4] i2c: designware: Ensure tx_buf_len is nonzero for SMBus block reads

From: Andy Shevchenko
Date: Thu Sep 17 2020 - 08:57:21 EST


On Wed, Sep 16, 2020 at 10:22:54PM -0700, Sultan Alsawaf wrote:
> From: Sultan Alsawaf <sultan@xxxxxxxxxxxxxxx>
>
> The point of adding a byte to len in i2c_dw_recv_len() is to make sure
> that tx_buf_len is nonzero, so that i2c_dw_xfer_msg() can let the i2c
> controller know that the i2c transaction can end. Otherwise, the i2c
> controller will think that the transaction can never end for block
> reads, which results in the stop-detection bit never being set and thus
> the transaction timing out.
>
> Adding a byte to len is not a reliable way to do this though; sometimes
> it lets tx_buf_len become zero, which results in the scenario described
> above. Therefore, just directly ensure tx_buf_len cannot be zero to fix
> the issue.

I got only patch 2/4, where the other 3 along with cover letter?

--
With Best Regards,
Andy Shevchenko