i.MX Processors中的主题 Re: UART as wake up source

UART as wake up source

vishakh — Sat, 27 Dec 2014 09:36:41 GMT

I am using UART as wake up source in linux kernel 2.6.35.3.

If I send 300 bytes from the system to the board when board is in low power state, in board side first 36 bytes are missing after system wake up.

Is this the expected behavior or else will I be able to receive all the data sent while resuming from low power mode to normal mode?

Regards,

Vishakh

igorpadykov — Sat, 27 Dec 2014 11:27:57 GMT

Hi Vishakh

first byte may be missed, this is expected behaviour,

if you are using dma (dma is made up of a 36-byte fifo), below patches are recommended.

Best regards

igor

vishakh — Mon, 05 Jan 2015 12:49:56 GMT

Hi Igor,

Thank you for the reply.

I tried to increase the UART3_DMA_RXBUFSIZE to 2048. But this is not solving the issue.

As I increase the baud rate, more bytes are missing.

Will you please let me know is there any other way to solve this issue?

It will be helpful if you explain how UART will receive the data on imx53 while resuming from the suspended state.

Regards,

Vishakh

igorpadykov — Mon, 05 Jan 2015 15:14:18 GMT

Hi Vishakh

are you using flow control for DMA ?

UART flow control should be used for DMA.

~igor