Le jeudi 5 décembre 2019 11:35:36 CET, vous avez écrit :
> Am Donnerstag, den 05.12.2019, 01:40 +0100 schrieb Éric Brunet:
> > I am not sure what information to provide. Here is what happens in dmesg
> 
> > when I plug in the DVD:
> Hi,
> 
> we need "lsusb -v" for both the error and the working case and "dmesg"
> for the working and the failing case (clearly labled please) and
> depending on that maybe a usbmon trace later on.


Hi, thanks for your interest.

nonworking case:
----------------
Shut down the computer, boot, log in, plug the dvd player, wait for the motor to stop, check that 
the reported size is wrong (1GiB only), run "dmesg" and "sudo lsusb -v"

working case:
-------------
Shut down the computer, plug the dvd player, boot, log in, check that the reported size is 
correct (6.9 GiB), run "dmesg" and "sudo lsusb -v"

I am attaching the dmesg for both cases, but only the lsusb for the non-working case, because it 
is easier to give the diff:

% diff -U0 lsusb_nonworking lsusb_working 
--- lsusb_nonworking    2019-12-05 12:06:02.541757500 +0100
+++ lsusb_working       2019-12-05 12:09:32.281072735 +0100
@@ -293 +293 @@
-Bus 001 Device 003: ID 0489:e0a2 Foxconn / Hon Hai 
+Bus 001 Device 004: ID 0489:e0a2 Foxconn / Hon Hai 
@@ -543 +543 @@
-Bus 001 Device 002: ID 0c45:6723 Microdia Integrated_Webcam_HD
+Bus 001 Device 003: ID 0c45:6723 Microdia Integrated_Webcam_HD
@@ -1054 +1054 @@
-Bus 001 Device 004: ID 0e8d:1887 MediaTek Inc. HP External USB Optical Drive
+Bus 001 Device 002: ID 0e8d:1887 MediaTek Inc. HP External USB Optical Drive

Thanks,

        Éric Brunet