Clemens Ladisch <clemens-P6GI/4k7KOmELgA04lAiVw(a)public.gmane.org>
writes:
David Kastrup wrote:
Or it talks with the host and says "I want
1A of current or 2A" and the
host says "no way".
Its descriptors claim that it wants 0 mA.
But it's delivered by default with a
two-host-plug USB cable
So it needs more power than a single plug could supply?
Ostensibly it's 2x5W of output. It runs without complaint on a single
plug when using Analog In, and shuts down in USB mode. I doubt that the
digital part takes up more than one plug can deliver...
and would not
be able to know about the power available from the
power-only plug. And it doesn't complain when running from the analog
input either, so it would be somewhat strange to just shut down when in
USB mode.
After a short time, it just stops reacting to USB requests.
It might be possible that some capacitor does no longer work correctly,
and that its internal voltage drops too far when actually doing things.
This would imply that it doesn't work in Windows either.
Well, the Windows PC disagrees. And the thing obviously has a whole lot
more volume reserves in USB mode: apparently the AUX in levels are badly
matched to typical sources.
I tried disabling autosuspend on USB by blacklisting in /etc/default/tlp
but it doesn't seem to help:
+++ USB
Autosuspend = enabled
Device whitelist = (not configured)
Device blacklist = 04a9:220e 10d6:1100
WWAN blacklist = enabled
Bus 002 Device 030 ID 07c4:a827 control = auto, autosuspend_delay_ms = 2000 -- Datafab
Systems, Inc. (usb-storage)
Bus 002 Device 001 ID 1d6b:0002 control = auto, autosuspend_delay_ms = 0 -- Linux
Foundation 2.0 root hub (hub)
Bus 007 Device 001 ID 1d6b:0001 control = auto, autosuspend_delay_ms = 0 -- Linux
Foundation 1.1 root hub (hub)
Bus 006 Device 001 ID 1d6b:0001 control = auto, autosuspend_delay_ms = 0 -- Linux
Foundation 1.1 root hub (hub)
Bus 005 Device 032 ID 10d6:1100 control = on, autosuspend_delay_ms = 2000 -- Actions
Semiconductor Co., Ltd MPMan MP-Ki 128 MP3 Player/Recorder (snd-usb-audio)
Bus 005 Device 001 ID 1d6b:0001 control = auto, autosuspend_delay_ms = 0 -- Linux
Foundation 1.1 root hub (hub)
Bus 001 Device 001 ID 1d6b:0002 control = auto, autosuspend_delay_ms = 0 -- Linux
Foundation 2.0 root hub (hub)
Bus 004 Device 001 ID 1d6b:0001 control = auto, autosuspend_delay_ms = 0 -- Linux
Foundation 1.1 root hub (hub)
Bus 003 Device 001 ID 1d6b:0001 control = auto, autosuspend_delay_ms = 0 -- Linux
Foundation 1.1 root hub (hub)
(tricky to time switching it on at the right moment so that tlp-stat
will see it before it turns off again). Switching autosuspend off
altogether does not help either.
Powered hub in the middle: the Boomster stays on _until_ I connect the
hub to the laptop. Then it identifies itself to the laptop and switches
off.
Really does not sound to me like it's an issue of digital power: then it
should not work under Windows I think, even granted that this is quite a
different type of laptop.
--
David Kastrup