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Re: [PATCH] rt2x00: Provide regulatory hint with rt2500pci/usb

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On 01/06/09 22:51, Ivo van Doorn wrote:
On Tuesday 06 January 2009, Luis R. Rodriguez wrote:
On Tue, Jan 06, 2009 at 12:39:34PM -0800, Gertjan van Wingerde wrote:
On 01/06/09 18:47, Ivo van Doorn wrote:
On Tuesday 06 January 2009, Luis R. Rodriguez wrote:

On Tue, Jan 06, 2009 at 09:32:20AM -0800, Ivo van Doorn wrote:

2. I'm still puzzled how to handle the two different values that the EEPROM has, namely one for the bg band and one for the a band. I've handled it by registering the one associated with the configured band, but that seems to be unlikely to be correct. I still haven't found a better way to handle this.

Because of this I hadn't looked very deep into rt61 and rt73 yet.


The problem isn't there for the bits that Ivo sent, as the rt2500 devices don't support the a band.

For rt2500pci and rt2500usb there are chipsets which support 5GHz (they are rare, but they do exist),
comments for the Ralink drivers indicate they simply didn't add the regulatory domain definitions yet.

Based on the documentation from the EEPROM for all devices I read that its recommended
that the EEPROM *not be relied on for the regulatory domain*, instead it recommends the
windows registry be used.

Based on tests for the devices with only one band, do are you seeing an actual regulatory
domain in the EEPROM?

I have to check, but I don't think I have any hardware with valid domain values.


To deal with the issue of having two separate EEPROM values for a regulatory domain
and since the documentation indicates to not rely on it I would advise to allow users
to be compliant by selecting the country they are in. wpa_supplicant has support for
selecting country now, and so does iw. Eventually I see Network Manager letting users
select the country. But you guys are the maintainers and developers so you will know
better.

Well it is fine with me,  understood from earlier discussion that it was advised that drivers
attempted to set the domain if they could. Hence the reason I had added reading the EEPROM
for domain values to the TODO list. But it is true that it is quite rare that there are valid values
for it. So it would be fine with me by letting the user handle it completely.

I see -- well if there are *some* cards that do have valid EEPROM values then it seems worth it
to do the actual regulatory_hint(), for dual band cards you can probably just not support it. But
its up to you guys. Just my advice based on the documentation I have read so far.

Ok.

Gertjan, do you know if there is any hardware with valid GEO data in the EEPROM?

As mentioned in my previous email, I do have devices that have valid GEO
data in the EEPROM. So, we should be able to use that.
Also, for the dual band cards, it does seem that at least the numerical
values are similar for both bands (although I'm not sure that same
numerical values means same regulatory domain). This is at least the
case on all the cards that I own.
If that's the case and since dual band cards will most likely have 2ghz support
why not just provide regulatory_hint() based on the 2ghz band all the time?

Sounds like the most reasonable solution to me as well.

I had a *slightly* more sophisticated model in mind: Check for dual-band devices whether the EEPROM values match. If they do, provide the regulatory_hint(), if they don't then just log an error, stating that the EEPROM cannot make up its mind in which geography it belongs. Just to prevent some unexpected behavior for devices that don't have sane EEPROM values.

However, that is all based on the assumption that we can match the numerical values of the two band geography domains. So far I haven't been able to establish that, and, moreover, the a-band field allows for values 0-10 where the bg-band field allows for values 0-7. So, we have to start matching these values against their defined allowed channels, and against the regulatory definitions, to see if we can actually match the values.

---
Gertjan
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