From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roosen Henri Date: Mon, 3 Dec 2018 14:44:09 +0000 Subject: [U-Boot] [BUG] serial: ns16550: missing characters on serial output of rk3399 board Message-ID: <1543848249.4005.15.camel@ginzinger.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: u-boot@lists.denx.de Since u-boot Commit 6f57c34473d3 (serial: ns16550: fix debug uart putc called before init) the serial output from SPL boot on my rk3399 board is missing characters. Without the commit SPL-boot puts out a string "U-Boot SPL board init", when this commit is in, the rk3399 board only prints a few of the characters of that string ("U-o Lodnt"). Reading the thread at https://patchwork.ozlabs.org/patch/955765/, I agree with Marek that "The real problem I believe is that someone can call debug UART print/read functions before it is inited". IMHO commits like these which try to make _debug_uart_putc() somewhat work without a proper _debug_uart_init() don't make sense; fighting sympthoms mostly leads to problems. Question is: what are the design decisions regarding _debug_uart_init() and _debug_uart_putc()?  * if _debug_uart_putc() is not allowed before _debug_uart_init(), then that is what is broken and should be fixed.  * if _debug_uart_putc() is allowed before _debug_uart_init(), then implementations of _debug_uart_putc() should ignore printing until _debug_uart_init() has been called. If a subsystem (like GD?) is required to properly implement that design, then that subsystem should be guaranteed to be available before any _debug_uart_putc() call... So there is some design information needed, or probably it is available and I'm not familiar with it (I'm not an active u-boot developer). Please share the information with who is trying to properly fix the initial issue. Thanks, Henri -------------- next part -------------- A non-text attachment was scrubbed... Name: smime.p7s Type: application/x-pkcs7-signature Size: 3608 bytes Desc: not available URL: