Hello Ondrej, Am 16.12.19 um 20:42 schrieb Ondřej Jirman: > Hello Stefan, > > On Mon, Dec 16, 2019 at 07:28:04PM +0100, Stefan Wahren wrote: >> Hi Ondrej, >> >> sorry, i don't have access to a Orange Pi 3. >> >> I looked at a AP6256 datasheet [1], but i couldn't find any helpful >> information about flow control during power up. >> >> Are you able to analyze this issue more further before we revert this patch? > I'd like to, but I'll not be able to attach logic probe to the AP6256 > module. It's too fine pitch for soldering. this the same issue, i had with the Raspberry Pi 4 :-( > I may try setting CTS/RTS to gpio/input mode and grab the capture of > the GPIO port states in time to see what's happening during probe > of bt_bcm module. > > I don't really understand what effect your patch is supposed to have > on the CTS/RTS lines during power up from the commit description. > Can you please explain it more concretely? I hope a picture explain more than thousand words. Please look at figure 7 at page 22 of the datasheet [2]. The patch tries to achieve the proper timing of BT_UART_CTS_N. > > I'll be able to get to playing with this after the holidays. Okay Stefan [2] - https://www.verical.com/datasheet/cypress-semiconductor-combo-wireless-module-cyw43455xkubgt-5770595.pdf