Re: [PATCH v3] dmaengine: rcar-dmac: use TCRB instead of TCR for residue

[Kuninori Morimoto]

Hi Geert

> Large serial console input (copy and pasting long lines) works, as that uses
> DMA. Small serial console input (typing) doesn't work.
>
> Apparently for the serial port, TCR contains the value we need (< 0x20),
> while TCRB always contains 0x20.
> Perhaps the code should use the minimum of both registers instead?

TCR(= read) happen 1st, and TCRB (= write) happen next.
"TCRB always contains 0x20" means, DMA didn't transfer data for some reason ?

"use minimum" idea can't guarantee data transfering, same as previous topic I guess.

Best regards
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Kuninori Morimoto