slorquet opened a new issue, #7138: URL: https://github.com/apache/incubator-nuttx/issues/7138
Hi, The stm32h7 does not properly drain the UARTs on close(). The console works perfectly and hides the problem, because nsh keeps the UART opened indefinitely. However, a custom program that sends data to an UART sporadically (like the built in command echo or an application that open/write/close) shows this important issue. echo does not even emit anything if I write less than 16 characters, which happens to be half the DMA buffer / cache line size (no idea if this is related). This is not a buffering issue as sending several small chunks in succession does not lead to the delayed emission of a large block. in my program, cfmakeraw does not change anything. calling tcdrain before close does nothing either. Inserting a one second delay after a serial write ( with sleep(1) ) allows my output to be written. Leaving the UART open in my program does not help, since the devices are closed after the program ends. This also happens in the echo command. Disabling DMA peripherals and options entirely has no effect and I dont think it's wise since the serial driver and others parts of the stm32h7 serial code clearly assumes DMA is enabled. I wonder if there are bugs in the stm32h7 driver, specifically related to DMA or something else, or if the issue is known, or if I missed some config options. Any help investigating this is highly appreciated, since the serial driver is surprisingly complex and I do not know how to start debugging this dynamic issue. It can probably be reproduced in ANY stm32h7 board with a secondary uart and the echo command. Thanks -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@nuttx.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
