Hi Pali, On Thu, 25 Nov 2021 at 19:10, Pali Rohár <[email protected]> wrote: > > On Thursday 25 November 2021 18:16:15 Loic Poulain wrote: > > Add support for CDC ACM using the new UDC and gadget API. This protocol > > can be used for serial over USB data transfer and is widely supported > > by various OS (GNU/Linux, MS-Windows, OSX...). The usual purpose of > > such link is to access device debug console and can be useful for > > products not exposing regular UART to the user. > > > > A default stdio device named 'usbacm' is created, and can be used > > to redirect console to USB link over CDC ACM: > > > > > setenv stdin usbacm; setenv stdout usbacm > > > > Signed-off-by: Loic Poulain <[email protected]> > > --- > > v2: - remove possible infinite recursipe print loop > > - Remove acmconsole command, start function along the stdio device > > v3: - Use __constant_cpu_to_le16() when possible > > - Rename stdio dev to 'usbacm' > > - Rename init function to drv_usbacm_init > > Hello! Just one question: is in this v3 patch fixed stdout-only > configuration, or it still has a bug which you described in email? > https://lore.kernel.org/u-boot/CAMZdPi8185pAiO4w2QYMtWGAFJiX=ej_bjw1cusre990wr7...@mail.gmail.com/ > > Because neither in above change long nor in driver help description nor > in driver source code is any comment related to stdout-only device.
No, actually it ended not being an issue, we can have it stdout/stdin independently. The driver loops on 'irq'-handling to ensure the USB controller has completely flushed TX before returning. > > Note that stdout-only does not have to be too uncommon. For example > Nokia N900 has enabled UART, keyboard+lcd and usbtty by default and > sometimes I enabled input only from keyboard and looked at usbtty > terminal (as stdout-only) if everything is working fine (that every > pressed key on keyboard was echoed correctly back to usbtty). Yes, checked this case on a imx7d based board and stdout-only works as you describe. Regards, Loic
