On Saturday 13 December 2008, Karthik Kumar wrote: > On Sat, Dec 13, 2008 at 9:53 PM, Stefan Monnier > > <[email protected]> wrote: > >> There are still hardware problems that exist with almost every > >> freerunner out there (GPS signal levels, for one). I would like to > >> see them fixed by Openmoko, Inc. > > The kernel fix for GPS is a mere quirk. Ideally it should get fixed in > hardware. I am sure that Openmoko's GTA03 changes include a > replacement of the existing u-blox. Is Openmoko considering fixing the > GPS?
You appear to be misinformed. The kernel fix enables the hardware SD drive strength control. This is _not_ a mere quirk - reducing EMI is one of the reasons hardware manufacturers include such a hardware feature. The early kernels had the drive strength hardcoded to the highest value which was higher than necessary in this hardware configuration, and caused interference problems. This was a software bug, and was fixed in later kernels by setting a lower default drive strength that is appropriate to the hardware implementation. This reduces EMI to the point that the ublox gps module performs to specification with the internal antenna even during writes to the SD, and generally outperforms my Garmin Geko 201. You may have been thinking of the earlier kernel fix which disabled the SD clock when it wasn't necessary, where previously it had been running continuously. This also reduced EMI when no data transfers were happening, but should be employed to reduce power consumption anyway. Both fixes are exposed as parameters in sysfs, so you can adjust the drive strength, and enable the clock permanently if you wish. There is a script in the wiki that will cycle through the possible settings recording TTFF so you can see the effects for yourself. Note that you need to disable any gps daemons before running it, and it will take a long time too run. When both are unassisted it also gets a fix faster and more reliably than a friend's N95. The N95 uses a different form of assistance, and when assisted it can get a fix faster than the GTA02, and in locations the GTA02 can't. I have yet to try the GTA02 assisted. _______________________________________________ support mailing list [email protected] https://lists.openmoko.org/mailman/listinfo/support
