Re: [PATCH 1/1] New driver: rtl8xxxu (mac80211)

[Jakub Sitnicki <jsitnicki@gmail.com>]

Hi Jes,

On Sat, Aug 29, 2015 at 11:18 PM CEST, Jes.Sorensen@redhat.com wrote:
> This is an alternate driver for a number of Realtek WiFi USB devices,
> including RTL8723AU, RTL8188CU, RTL8188RU, RTL8191CU, and RTL8192CU.
> It was written from scratch utilizing the Linux mac80211 stack.
>
> After spending months cleaning up the vendor provided rtl8723au
> driver, which comes with it's own 802.11 stack included, I decided to
> rewrite this driver from the bottom up.

In the long term, do you plan for this driver to support the
RTL8188EU-based devices as well?

I've been checking how far I can get through the rtl8xxxu initialization
using a TP-Link TL-WN725N dongle without changing too much.

Getting it up to read the EFUSE contents wasn't difficult but then you
need to parse it and first differences come to light.  Namely, TX power
levels are defined per each of 6 (not 3) channel groups, and power
differences are defined per TX path (as opposed to per channel group).
This is perhaps better described by the relevant structure from
rtl8188eu driver:

struct txpowerinfo24g {
	u8 IndexCCK_Base[MAX_RF_PATH][MAX_CHNL_GROUP_24G];
	u8 IndexBW40_Base[MAX_RF_PATH][MAX_CHNL_GROUP_24G];
	/* If only one tx, only BW20 and OFDM are used. */
	s8 CCK_Diff[MAX_RF_PATH][MAX_TX_COUNT];
	s8 OFDM_Diff[MAX_RF_PATH][MAX_TX_COUNT];
	s8 BW20_Diff[MAX_RF_PATH][MAX_TX_COUNT];
	s8 BW40_Diff[MAX_RF_PATH][MAX_TX_COUNT];
};

AFAICT, in this regard, rtl8188eu driver has more in common with the
rtlwifi/rtl8188ee driver.

I'm curious what is your opinion on this.  In particular, do you see any
reason not to make an attempt to extend rtl8xxxu to support 8188EU
chips?

Thanks,
Jakub