On Mon, Sep 05, 2022 at 11:31:15AM +0200, Pali Rohár wrote: > On certain places it is required to flush output print buffers to ensure > that text strings were sent to console or serial devices. For example when > printing message that U-Boot is going to boot kernel or when U-Boot is > going to change baudrate of terminal device. > > Some console devices, like UART, have putc/puts functions which just put > characters into HW transmit queue and do not wait until all data are > transmitted. Doing some sensitive operations (like changing baudrate or > starting kernel which resets UART HW) cause that U-Boot messages are lost. > > Therefore introduce a new flush() function, implement it for all serial > devices via pending(false) callback and use this new flush() function on > sensitive places after which output device may go into reset state. > > This change fixes printing of U-Boot messages: > "## Starting application at ..." > "## Switch baudrate to ..." > > Changes in v3: > * add macro STDIO_DEV_ASSIGN_FLUSH() > * fix commit messages > * remove changes from serial.c > > Changes in v2: > * split one big patch into smaller 6 patches > * add config option to allow disabling this new function > > Pali Rohár (6): > sandbox: Add function os_flush() > console: Implement flush() function > serial: Implement flush callback > serial: Implement serial_flush() function for console flush() fallback > serial: Call flush() before changing baudrate > boot: Call flush() before booting
Including the change you suggested to 4/6 to fix that build issue, there's at least one more large issue that prevents CI from getting too far: https://source.denx.de/u-boot/u-boot/-/pipelines/13534 and they all have a failure similar to: https://source.denx.de/u-boot/u-boot/-/jobs/500794#L51 Please see https://u-boot.readthedocs.io/en/latest/develop/ci_testing.html for how to run CI on the world yourself before submitting v4. Thanks! -- Tom
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