On Mon, Jun 1, 2009 at 07:20, Andrés Ambrois <[email protected]> wrote: > On Sunday 31 May 2009 11:15:58 am Tomeu Vizoso wrote: >> On Sun, May 31, 2009 at 16:09, Tiago Marques <[email protected]> wrote: >> > On 5/31/09, John Watlington <[email protected]> wrote: >> >> On May 30, 2009, at 12:04 PM, Reinder E.N. de Haan wrote: >> >>> Subject: Xo 1.5 wlan >> >>> Date: Thu, 07 May 2009 19:56:27 +0200 >> >>> From: Reinder de Haan <[email protected]> >> >>> To: John Watlington <[email protected]> >> >>> >> >>> Hello, >> >>> >> >>> I have a couple of questions regarding the wlan module in xo 1.5; >> >>> >> >>> 1) will it be an off the shelf module (3th party) or a quanta/olpc >> >>> 'private' module >> >> >> >> One of the complications of the Gen 1.5 design has been improving >> >> the WLAN module. The existing module takes lots of power, and >> >> the USB driver still needs extensive modification to speed up >> >> suspend/resume. >> > >> > Being power the major concern, will wireless range also be enhanced in >> > some way? Most of the early claims that the XO had a top class >> > wireless range have not materialized, at least when I compare it to >> > other devices like a Fon2100 or an IPW2200 from Intel, which is >> > probably the device with best wireless range that I've ever seen. >> > >> > A way to change the transmit power in software would be great for >> > power and range, depending on the application. Does the module have >> > anything like that or are you just mainly focusing on power and >> > relegating range to 2nd place? >> >> I think that there have been recent improvements in the algorithm for >> choosing the transmission power in the linux kernel. I'm not sure if >> all wifi drivers benefit from it, but a laptop with b43 has improved >> dramatically its range after updating to Ubuntu Jaunty. > > I think what you're talking about is the rate selection algorithm, I dont > think the kernel dynamically changes the Tx power.
Ok, then it may have been a improvement in that particular wifi driver. Regards, Tomeu > Linux has moved to minstrel [0] as its default rate control algorithm, which > is way better than what we had previously in dealing with lots of collisions, > where slower rates may not increase the chance of getting a packet through. > This scenario is common in schools with lots of XOs. > > Some drivers still have their own algorithm, it is probable that the closed > fullmac Marvell implementation has one. > > [0] > http://linuxwireless.org/en/developers/Documentation/mac80211/RateControl/minstrel > > >> >> > Best regards, >> > >> > Tiago Marques >> > >> >> Unlike Gen 1, we don't have the time or expected market to >> >> develop and certify a custom module. >> >> >> >> The current plan is to use an existing WLAN module, based on >> >> the Marvell 88W8686 and connected to the system using an >> >> SDIO interface. >> >> >> >>> 2) if it is a private module please break out jtag and the serial port >> >>> for debugging (xo 1.0 only had jtag.. serial ended right at the >> >>> balls of >> >>> the chip :-( >> >> >> >> Sorry, the module doesn't bring any of the internal debugging signal >> >> out. >> >> >> >>> 3a) if its a 3th party moduel is it posible to buy it somewhere ? >> >> >> >> Yes and no. There are 88W8686-based SDIO modules already >> >> available, and electrically/software-wise they will be identical to the >> >> one we are planning to use. >> >> >> >> The actual module used in XO-1.5 will have a half-height miniPCI-e >> >> form factor. Even if you could buy it in small quantities, you >> >> would have >> >> to arrange an adapter board to use internally. >> >> >> >> Cheers, >> >> wad > _______________________________________________ Devel mailing list [email protected] http://lists.laptop.org/listinfo/devel
