Re: [PATCH] Revert "USB: serial: ch341: add new Product ID for CH341A"

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Feb 07, 2022 at 02:08:23AM +0200, Dmytro Bagrii wrote:
> This reverts commit 46ee4abb10a07bd8f8ce910ee6b4ae6a947d7f63.

You forgot to cc: the author of that commit, why?

Also forgot to cc: the maintainer of the driver/subsytem?

> CH341A has three different modes of operation selectable either by
> hardware pin connections or by external EEPROM configuration. Each
> mode is represented by corresponding product ID:
> 
> 0x5523: Asyncronous Serial Interface
> 0x5584: Parallel Printer Interface
> 0x5512: EPP/MEM Interface

That does not corrispond with what Jan-Niklas said in the original
commit.

> 
> (See "5.3.Function configuration" in datasheet at wch-ic.com/downloads/CH341DS1_PDF.html)
> 
> When CH341A is configured as EPP/MEM Interface it appears as 1a86:5512 and being mistakenly
> handled by ch341 USB serial driver.
> 
> It is possible to use CH341A in EPP/MEM mode only if ch341 module is blacklisted, but it must be
> unblacklisted every time to use CH341A as a serial converter. Also obviously it is impossible
> to use two CH341A boards in different modes simoultaneously.

Please wrap your lines at 72 columns.

thanks,

greg k-h