Bug#980750: thanks a lot an bye ...

[alain <compte.perso.de-alain@bbox.fr>]

I would like to thank you all for your help.

now, debian supports big navi graphics cards.

to start with, "navy21" cards are supported.
AMD RX 6800 /6800 XT /6900 XT
The 6700 and, perhaps, the 6500 are still to come.

With gcn3.0 support now enabled, it is likely that the RX 6x00 
generation will be fully supported.

remains a question : how did you know where the error came from ? and 
what to modify ?

respectfully .

alain.

p.s. you can close this thread.