Hi!
If that does the job we need to somehow inherit the power supply maximum
from
PCI when we allocate the root hub's device structure.
I don't think there is such a convention that's generic for PCI. There
might
be ACPI-specific tables holding that value, but on embedded
Am Montag, 5. Juni 2006 16:32 schrieb David Brownell:
On Saturday 03 June 2006 2:29 am, Oliver Neukum wrote:
If that does the job we need to somehow inherit the power supply maximum
from
PCI when we allocate the root hub's device structure.
I don't think there is such a convention
On Saturday 03 June 2006 2:29 am, Oliver Neukum wrote:
Am Dienstag, 30. Mai 2006 22:01 schrieb Pavel Machek:
Actually I have exactly opposite problem: my computer (spitz) can't
supply full 500mA on its root hub, and linux tries to power up
'hungry' devices, anyway, leading to very weird
Am Dienstag, 30. Mai 2006 22:01 schrieb Pavel Machek:
Hi!
Starting with 2.6.16, some USB devices fail unnecessarily on unpowered
hubs. Alan Stern explains,
The idea is that the kernel now keeps track of USB power budgets. When a
bus-powered device requires more current than its
Am Freitag, 2. Juni 2006 02:03 schrieb David Liontooth:
The MaxPower value does not appear to be a reliable index of this. My
USB stick has a MaxPower value of 178mA and works flawlessly off an
unpowered hub. Unfortunately devices don't seem to tell us what their
It works flawlessly on all
On Thu, 1 Jun 2006, David Liontooth wrote:
What are the reasons not to do this? What happens if a USB stick is
underpowered to one unit? Nothing? Slower transmission? Data loss? Flash
memory destruction? If it's just speed, it's a price well worth paying.
I do wish people would read the
Alan Stern wrote:
Trying to draw too much current from an unpowered hub can and does cause
data loss.
I consider this issue closed; thank you for looking at it. The
workaround is reasonably simple for the common situation of mounting a
USB stick on a keyboard, perhaps with a mouse attached
On Thu, 1 Jun 2006, linux-os (Dick Johnson) wrote:
If they do, they are violating the spec. A device in the unconfigured
(state 0)
state must not draw more than 100mA.
...
Hmmm, the USB-IF recommends 100 mA per port, not requires.
See section 7.2.1 of the USB 2.0 specification (p. 177):
On Thu, 1 Jun 2006, Oliver Neukum wrote:
Am Donnerstag, 1. Juni 2006 17:09 schrieb linux-os (Dick Johnson):
Many, most, perhaps all such devices don't take more power when they
are enabled. Everything is already running and sucking up maximum
current when you plug it in! If the motherboard
On Thu, 1 Jun 2006, Andrew Morton wrote:
On Thu, 1 Jun 2006 10:58:43 -0400 (EDT)
Alan Stern [EMAIL PROTECTED] wrote:
As an alternative, we could allow an over-budget window of say 10%.
That, plus we should provide a suitable i-know-what-im-doing user override,
with the appropriate
Andrew Morton wrote:
On Thu, 01 Jun 2006 02:18:20 -0700
..
This is generating a lot of grief and appears to be unnecessarily
strict. Common USB sticks with a MaxPower value just above 100mA, for
instance, typically work fine on unpowered hubs supplying 100mA.
Is a more user-friendly
Lennart Sorensen [EMAIL PROTECTED] writes:
A scanner certainly uses more power with the scanner light on than with
it off, and it starts out off until it is in use on most scanners. Of
course I have never seen a usb powered scanner, so it doesn't seem to
matter.
Oh, they've been around for
Greg KH wrote:
On Thu, Jun 01, 2006 at 10:58:43AM -0400, Alan Stern wrote:
On Thu, 1 Jun 2006, Andrew Morton wrote:
On Thu, 01 Jun 2006 02:18:20 -0700
David Liontooth [EMAIL PROTECTED] wrote:
Starting with 2.6.16, some USB devices fail unnecessarily on unpowered
hubs.
On Thursday 01 June 2006 5:03 pm, David Liontooth wrote:
However, obeying the USB power rules is not an end in itself -- the
relevant question is the minimum power the device requires to operate
correctly and without damage.
We don't know the minimum, or much care about it since the minimum
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