Jiri Pirko <j...@resnulli.us> writes:
> Mon, Jun 02, 2014 at 04:25:15PM CEST, mpriv...@redhat.com wrote:
>>The link speed is available at /sys/class/net/$nic/speed.
>>However, the speed is printed in unsigned integer format. This
>>makes userspace applications read an incorrect value (which
>>moreover changes through several architectures) while in fact
>>'-1' should be reported.
>>
>>Before the change:
>> # cat /sys/class/net/eth0/speed
>> 4294967295
>>
>>After the change:
>> # cat /sys/class/net/eth0/speed
>> -1
>>
>>Signed-off-by: Michal Privoznik <mpriv...@redhat.com>
>>---
>> net/core/net-sysfs.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>>diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
>>index 1cac29e..99afdea 100644
>>--- a/net/core/net-sysfs.c
>>+++ b/net/core/net-sysfs.c
>>@@ -173,7 +173,7 @@ static ssize_t speed_show(struct device *dev,
>> if (netif_running(netdev)) {
>> struct ethtool_cmd cmd;
>> if (!__ethtool_get_settings(netdev, &cmd))
>>- ret = sprintf(buf, fmt_udec, ethtool_cmd_speed(&cmd));
>>+ ret = sprintf(buf, fmt_dec, ethtool_cmd_speed(&cmd));
>
> I wonder why this should be signed. What -1 means? What driver reports
> this?
I believe many drivers will do this when the speed is unknown, e.g
because the link is down. For example:
bjorn@nemi:~$ grep . /sys/class/net/eth0/speed
4294967295
bjorn@nemi:~$ ls -l /sys/class/net/eth0/device/driver
lrwxrwxrwx 1 root root 0 Jun 2 10:48 /sys/class/net/eth0/device/driver ->
../../../bus/pci/drivers/e1000e
bjorn@nemi:~$ ethtool eth0
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Speed: Unknown!
Duplex: Unknown! (255)
Port: Twisted Pair
PHYAD: 2
Transceiver: internal
Auto-negotiation: on
MDI-X: Unknown
Cannot get wake-on-lan settings: Operation not permitted
Current message level: 0x00000007 (7)
drv probe link
Link detected: no
Bjørn
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