From: Daniel Drake <[EMAIL PROTECTED]>
2.6.16 introduces USB power budgeting in the Linux kernel, and since then, a
fair number of users have observed that some of their devices no longer work in
unpowered hubs (this is not a bug, the devices claim that they need more than
100mA).
The very least we can do is print an informational message to the kernel log
when this happens, otherwise it is not at all clear why the device was not
accepted.
Signed-off-by: Daniel Drake <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
drivers/usb/core/hub.c | 10 +++++++++-
1 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 1b1846e..89ebe6a 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1176,6 +1176,7 @@ static int choose_configuration(struct u
{
int i;
int num_configs;
+ int insufficient_power = 0;
struct usb_host_config *c, *best;
best = NULL;
@@ -1228,8 +1229,10 @@ #endif
*/
/* Rule out configs that draw too much bus current */
- if (c->desc.bMaxPower * 2 > udev->bus_mA)
+ if (c->desc.bMaxPower * 2 > udev->bus_mA) {
+ insufficient_power++;
continue;
+ }
/* If the first config's first interface is COMM/2/0xff
* (MSFT RNDIS), rule it out unless Linux has host-side
@@ -1263,6 +1266,11 @@ #endif
best = c;
}
+ if (insufficient_power > 0)
+ dev_info(&udev->dev, "rejected %d configuration%s "
+ "due to insufficient available bus power\n",
+ insufficient_power, plural(insufficient_power));
+
if (best) {
i = best->desc.bConfigurationValue;
dev_info(&udev->dev,
--
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