On Thu, Jul 29, 2021 at 09:48:16AM +0800, Zhiyong Tao wrote: > This series includes 1 patches: > 1.fix uart corruption issue when rx power off > > when uart is used as a communication port with external device(GPS). > when external device(GPS) power off, the power of rx pin is also from > 1.8v to 0v. Even if there is not any data in rx. But uart rx pin can > capture the data "0". > If uart don't receive any data in specified cycle, uart will generates > BI(Break interrupt) interrupt. > If external device(GPS) power off, we found that BI interrupt appeared > continuously and very frequently. > When uart interrupt type is BI, uart IRQ handler(8250 framwork > API:serial8250_handle_irq) will push data to tty buffer. > The code path: > https://elixir.bootlin.com/linux/latest/source/drivers/tty/serial/8250/8250_port.c#L1917 > mtk8250_dma_rx_complete is a task of mtk_uart_apdma_rx_handler. > mtk8250_dma_rx_complete priority is lower than uart irq > handler(serial8250_handle_irq). > if we are in process of mtk8250_dma_rx_complete, uart appear BI > interrupt:1)serial8250_handle_irq will priority execution.2)it may cause > write tty buffer conflict in mtk8250_dma_rx_complete. > So the spin lock protect the rx receive data process is not break. All of this information should be in the changelog for the patch itself. There is no need for a "cover letter" for a single patch like this. Can you redo your 1/1 patch and add the above information to the changelog text and resend it as a v2? thanks, greg k-h
