On Wed, Jul 20, 2011 at 02:58:20PM +0300, Kalle Valo wrote:
> On 07/20/2011 02:38 PM, Ben Hutchings wrote:
> > On Wed, 2011-07-20 at 12:18 +0300, Kalle Valo wrote:
> >> cfg80211 exports zero length register size as it currently only uses
> >> struct ethtool_regs.version to export struct wiphy.hw_version.
> > [...]
> >
> > The ethtool_regs::version field represents the version of the register
> > dump format. This may or may not relate to a hardware version.
This seems like a strange claim to make...?
struct ethtool_regs {
__u32 cmd;
__u32 version; /* driver-specific, indicates different chips/revs */
__u32 len; /* bytes */
__u8 data[0];
};
That "indicates different chips/revs" comment has been there at least
as long as the kernel has been in git (back to the 2.6.12 era).
> > If you don't actually provide a register dump then don't implement this
> > operation.
>
> Then we have a problem as cfg80211 exports the hw version without any
> register dumps:
>
> static int cfg80211_get_regs_len(struct net_device *dev)
> {
> /* For now, return 0... */
> return 0;
> }
>
> static void cfg80211_get_regs(struct net_device *dev, struct
> ethtool_regs *regs,
> void *data)
> {
> struct wireless_dev *wdev = dev->ieee80211_ptr;
>
> regs->version = wdev->wiphy->hw_version;
> regs->len = 0;
> }
>
> And this has been there a long time already. How cfg80211 should export
> hw version if this is not a proper way?
The ethool binary already has support for the at76c50x_usb driver,
which uses this very mechanism in exactly this way. I know this
worked previously, although I don't know what might have changed to
break it...?
John
--
John W. Linville Someday the world will need a hero, and you
linville@xxxxxxxxxxxxx might be all we have. Be ready.
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