rt2500usb broken since 2.6.29

rt2500usb broken since 2.6.29

[Ondrej Zary]

Hello,
rt2500usb is broken since kernel 2.6.29. It has been discussed before but 
never solved:
http://rt2x00.serialmonkey.com/phpBB/viewtopic.php?f=4&t=4834
https://bugzilla.redhat.com/show_bug.cgi?id=484888

I have Asus WL-167G and it really does not work. Scanning works, association 
too but no packets can be sent (looks like receive works because tcpdump 
shows packets from other machines). DHCP fails (No DHCPOFFERS received).

The problem is caused by this patch:

rt2x00: Implement HW encryption (rt2500usb)
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=dddfb478b26e29a2b47f655ec219e743b8111015

Removing it from 2.6.29 restores the functionality.

-- 
Ondrej Zary

[rt2x00-users] rt2500usb broken since 2.6.29

[Luis Correia]

Hi,

On Thu, Mar 18, 2010 at 21:46, Ondrej Zary <linux@rainbow-software.org> wrote:
>
> Hello,
> rt2500usb is broken since kernel 2.6.29. It has been discussed before but
> never solved:
> http://rt2x00.serialmonkey.com/phpBB/viewtopic.php?f=4&t=4834
> https://bugzilla.redhat.com/show_bug.cgi?id=484888
>
> I have Asus WL-167G and it really does not work. Scanning works, association
> too but no packets can be sent (looks like receive works because tcpdump
> shows packets from other machines). DHCP fails (No DHCPOFFERS received).
>
> The problem is caused by this patch:
>
> rt2x00: Implement HW encryption (rt2500usb)
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=dddfb478b26e29a2b47f655ec219e743b8111015
>
> Removing it from 2.6.29 restores the functionality.
>
> --
> Ondrej Zary
>

you can prevent hardware encryption by supplying "nohwcrypt=1" to the driver.
(modinfo rt2500usb)

Luis Correia
rt2x00 project admin

Re: [rt2x00-users] rt2500usb broken since 2.6.29

[Ondrej Zary]

On Thursday 18 March 2010 22:51:18 Luis Correia wrote:
> Hi,
>
> On Thu, Mar 18, 2010 at 21:46, Ondrej Zary 
<linux@rainbow-software.org>wrote:
> > Hello,
> > rt2500usb is broken since kernel 2.6.29. It has been discussed before but
> > never solved:
> > http://rt2x00.serialmonkey.com/phpBB/viewtopic.php?f=4&t=4834
> > https://bugzilla.redhat.com/show_bug.cgi?id=484888
> >
> > I have Asus WL-167G and it really does not work. Scanning works,
> > association
> > too but no packets can be sent (looks like receive works because tcpdump
> > shows packets from other machines). DHCP fails (No DHCPOFFERS received).
> >
> > The problem is caused by this patch:
> >
> > rt2x00: Implement HW encryption (rt2500usb)
> >
> > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit
> >;h=dddfb478b26e29a2b47f655ec219e743b8111015
> >
> > Removing it from 2.6.29 restores the functionality.
> >
> > --
> > Ondrej Zary
>
> you can prevent hardware encryption by supplying "nohwcrypt=1" to the
> driver.
> (modinfo rt2500usb)

That did not work. Maybe that was because I just unloaded the rt2500usb module 
and loaded it again with nohwcrypt=1 without rebooting the machine. Then I 
removed the HW encryption, recompiled and reloaded and it did not work 
either. It started to work only after reboot.

Does the HW encryption really work with any rt2500usb hardware? How can I help 
to fix it? Or maybe it should be disabled by default.

>
> Luis Correia
> rt2x00 project admin


-- 
Ondrej Zary

Re: [rt2x00-users] rt2500usb broken since 2.6.29

[Luis Correia]

Hi,
On Thu, Mar 18, 2010 at 22:04, Ondrej Zary <linux@rainbow-software.org> wrote:
> On Thursday 18 March 2010 22:51:18 Luis Correia wrote:
>> Hi,
>>
>> On Thu, Mar 18, 2010 at 21:46, Ondrej Zary
> <linux@rainbow-software.org>wrote:
>> > Hello,
>> > rt2500usb is broken since kernel 2.6.29. It has been discussed before but
>> > never solved:
>> > http://rt2x00.serialmonkey.com/phpBB/viewtopic.php?f=4&t=4834
>> > https://bugzilla.redhat.com/show_bug.cgi?id=484888
>> >
>> > I have Asus WL-167G and it really does not work. Scanning works,
>> > association
>> > too but no packets can be sent (looks like receive works because tcpdump
>> > shows packets from other machines). DHCP fails (No DHCPOFFERS received).
>> >
>> > The problem is caused by this patch:
>> >
>> > rt2x00: Implement HW encryption (rt2500usb)
>> >
>> > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit
>> >;h=dddfb478b26e29a2b47f655ec219e743b8111015
>> >
>> > Removing it from 2.6.29 restores the functionality.
>> >
>> > --
>> > Ondrej Zary
>>
>> you can prevent hardware encryption by supplying "nohwcrypt=1" to the
>> driver.
>> (modinfo rt2500usb)
>
> That did not work. Maybe that was because I just unloaded the rt2500usb module
> and loaded it again with nohwcrypt=1 without rebooting the machine. Then I
> removed the HW encryption, recompiled and reloaded and it did not work
> either. It started to work only after reboot.

did you actually remove the usb module and unloaded the module as well?

you then need to load the module with the option, wait one sec and
then plug the device back in.

> Does the HW encryption really work with any rt2500usb hardware? How can I help
> to fix it? Or maybe it should be disabled by default.

I think the HW encription did work in the past, but I'm unsure of the
proper timeline.

Luis Correia
rt2x00 project admin

Re: [rt2x00-users] rt2500usb broken since 2.6.29

[Ondrej Zary]

On Thursday 18 March 2010, Luis Correia wrote:
> Hi,
>
> On Thu, Mar 18, 2010 at 22:04, Ondrej Zary <linux@rainbow-software.org> 
wrote:
> > On Thursday 18 March 2010 22:51:18 Luis Correia wrote:
> >> Hi,
> >>
> >> On Thu, Mar 18, 2010 at 21:46, Ondrej Zary
> >
> > <linux@rainbow-software.org>wrote:
> >> > Hello,
> >> > rt2500usb is broken since kernel 2.6.29. It has been discussed before
> >> > but never solved:
> >> > http://rt2x00.serialmonkey.com/phpBB/viewtopic.php?f=4&t=4834
> >> > https://bugzilla.redhat.com/show_bug.cgi?id=484888
> >> >
> >> > I have Asus WL-167G and it really does not work. Scanning works,
> >> > association
> >> > too but no packets can be sent (looks like receive works because
> >> > tcpdump shows packets from other machines). DHCP fails (No DHCPOFFERS
> >> > received).
> >> >
> >> > The problem is caused by this patch:
> >> >
> >> > rt2x00: Implement HW encryption (rt2500usb)
> >> >
> >> > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=com
> >> >mit ;h=dddfb478b26e29a2b47f655ec219e743b8111015
> >> >
> >> > Removing it from 2.6.29 restores the functionality.
> >> >
> >> > --
> >> > Ondrej Zary
> >>
> >> you can prevent hardware encryption by supplying "nohwcrypt=1" to the
> >> driver.
> >> (modinfo rt2500usb)
> >
> > That did not work. Maybe that was because I just unloaded the rt2500usb
> > module and loaded it again with nohwcrypt=1 without rebooting the
> > machine. Then I removed the HW encryption, recompiled and reloaded and it
> > did not work either. It started to work only after reboot.
>
> did you actually remove the usb module and unloaded the module as well?
>
> you then need to load the module with the option, wait one sec and
> then plug the device back in.
>
> > Does the HW encryption really work with any rt2500usb hardware? How can I
> > help to fix it? Or maybe it should be disabled by default.
>
> I think the HW encription did work in the past, but I'm unsure of the
> proper timeline.

HW encryption was added in 2.6.29 and it does not work there. In 2.6.30, the 
driver is broken even more - it does not work even with HW encryption 
disabled. I'm going to bisect it.

-- 
Ondrej Zary

Re: [rt2x00-users] rt2500usb broken since 2.6.29

[Ondrej Zary]

On Friday 19 March 2010 16:01:47 Ondrej Zary wrote:
> On Thursday 18 March 2010, Luis Correia wrote:
> > Hi,
> >
> > On Thu, Mar 18, 2010 at 22:04, Ondrej Zary <linux@rainbow-software.org>
>
> wrote:
> > > On Thursday 18 March 2010 22:51:18 Luis Correia wrote:
> > >> Hi,
> > >>
> > >> On Thu, Mar 18, 2010 at 21:46, Ondrej Zary
> > >
> > > <linux@rainbow-software.org>wrote:
> > >> > Hello,
> > >> > rt2500usb is broken since kernel 2.6.29. It has been discussed
> > >> > before but never solved:
> > >> > http://rt2x00.serialmonkey.com/phpBB/viewtopic.php?f=4&t=4834
> > >> > https://bugzilla.redhat.com/show_bug.cgi?id=484888
> > >> >
> > >> > I have Asus WL-167G and it really does not work. Scanning works,
> > >> > association
> > >> > too but no packets can be sent (looks like receive works because
> > >> > tcpdump shows packets from other machines). DHCP fails (No
> > >> > DHCPOFFERS received).
> > >> >
> > >> > The problem is caused by this patch:
> > >> >
> > >> > rt2x00: Implement HW encryption (rt2500usb)
> > >> >
> > >> > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=c
> > >> >om mit ;h=dddfb478b26e29a2b47f655ec219e743b8111015
> > >> >
> > >> > Removing it from 2.6.29 restores the functionality.
> > >> >
> > >> > --
> > >> > Ondrej Zary
> > >>
> > >> you can prevent hardware encryption by supplying "nohwcrypt=1" to the
> > >> driver.
> > >> (modinfo rt2500usb)
> > >
> > > That did not work. Maybe that was because I just unloaded the rt2500usb
> > > module and loaded it again with nohwcrypt=1 without rebooting the
> > > machine. Then I removed the HW encryption, recompiled and reloaded and
> > > it did not work either. It started to work only after reboot.
> >
> > did you actually remove the usb module and unloaded the module as well?
> >
> > you then need to load the module with the option, wait one sec and
> > then plug the device back in.
> >
> > > Does the HW encryption really work with any rt2500usb hardware? How can
> > > I help to fix it? Or maybe it should be disabled by default.
> >
> > I think the HW encription did work in the past, but I'm unsure of the
> > proper timeline.
>
> HW encryption was added in 2.6.29 and it does not work there. In 2.6.30,
> the driver is broken even more - it does not work even with HW encryption
> disabled. I'm going to bisect it.

Bisection revealed this commit:
ac7f9cfa2c3b810e0adfb889ad407a8c79a84dbe
cfg80211: accept no-op interface mode changes

Removing it from 2.6.30 (and disabling HW encryption) makes rt2500usb work in 
2.6.30. There are more changes to that code in next kernels so the patch 
cannot be removed from newer kernels. However, disabling it (by changing "if 
(change)" to "if (1)" in net/wireless/nl80211.c) and disabling HW encryption 
makes rt2500usb work even in 2.6.34-rc1.

There seems to be another (third!) problem. With 2.6.29, DHCP works on the 
first DHCPDISCOVER. With 2.6.30, it takes two to three DHCPDISCOVERs to get a 
reply. With 2.6.34-rc1, it takes three to five. After one reboot with 
2.6.34-rc1, it did not work at all with this in log:
phy0 -> rt2500usb_set_device_state: Error - Device failed to enter state 3 
(-16).

-- 
Ondrej Zary