Hauppauge USB TV tuner: inaccurate signal strength, always 100%
by nrnrnr from LinuxQuestions.org on (#5MW91)
I recently installed a USB dual tuner from Hauppauge: their WinTV-dualHD 01595 ATSC/QAM tuner, identified as USB ID 2040:826d. Tuning and recording works great; I can record two channels at once with no problems. But signal strength is always shown at 100%.
The signal strength is reported by an ioctl call with FE_READ_SIGNAL_STRENGTH. This call produces a 16-bit unsigned number which is always 65535. With my previous tuner (a very old PCHDTV PCI card) signal strength fluctuated and was typically reported in the high 70s or low 80s (when cast to floating point and divided by 655.35).
I'd be surprised if the tuner was that much better than the old card; it seems more likely that there is some sort of issue reporting the signal strength. Does anybody have any insights here? Like how to find the driver and maybe get a look at the source code?
The signal strength is reported by an ioctl call with FE_READ_SIGNAL_STRENGTH. This call produces a 16-bit unsigned number which is always 65535. With my previous tuner (a very old PCHDTV PCI card) signal strength fluctuated and was typically reported in the high 70s or low 80s (when cast to floating point and divided by 655.35).
I'd be surprised if the tuner was that much better than the old card; it seems more likely that there is some sort of issue reporting the signal strength. Does anybody have any insights here? Like how to find the driver and maybe get a look at the source code?