Il 23/02/2012 23:12, Hans-Frieder Vogt ha scritto: > Am Donnerstag, 23. Februar 2012 schrieb Gianluca Gennari: >> Il 22/02/2012 23:20, Hans-Frieder Vogt ha scritto: >>> I have written a driver for the AF9035 & AF9033 (called af903x), based on >>> the various drivers and information floating around for these chips. >>> Currently, my driver only supports the devices that I am able to test. >>> These are >>> - Terratec T5 Ver.2 (also known as T6) >>> - Avermedia Volar HD Nano (A867) >>> >>> The driver supports: >>> - diversity and dual tuner (when the first frontend is used, it is in >>> diversity mode, when two frontends are used in dual tuner mode) >>> - multiple devices >>> - pid filtering >>> - remote control in NEC and RC-6 mode (currently not switchable, but >>> depending on device) >>> - support for kernel 3.1, 3.2 and 3.3 series >>> >>> I have not tried to split the driver in a DVB-T receiver (af9035) and a >>> frontend (af9033), because I do not see the sense in doing that for a >>> demodulator, that seems to be always used in combination with the very >>> same receiver. >>> >>> The patch is split in three parts: >>> Patch 1: support for tuner fitipower FC0012 >>> Patch 2: basic driver >>> Patch 3: firmware >>> >>> Hans-Frieder Vogt e-mail: hfvogt <at> gmx .dot. net >> >> Hi Hans, >> thank you for the new af903x driver. >> A few comments: >> >> 1) I think you should set up a git repository with your driver and then >> send a PULL request to the list; as it is, the first patch is affected >> by line-wrapping problems so it must be manually edited to be >> applicable, and the second patch is compressed so it will be ignored by >> patchwork. >> >> 2) There are a couple of small errors in the patches (see my attached >> patches): in the dvb-usb Makefile, DVB_USB_AF903X must be replaced by >> CONFIG_DVB_USB_AF903X otherwise the driver will not compile; also, in >> the dvb_frontend_ops struct, the field info.type should be removed for >> kernels >= 3.3.0. >> >> 3) The USB VID/PID IDs should be moved into dvb-usb-ids.h (see patch 3); >> I also added a few IDs from the Avermedia A867 driver*. As your driver >> supports both AF9007 and mxl5007t tuners I think this is safe. >> >> *http://www.avermedia.com/Support/DownloadCount.aspx?FDFId=4591 >> >> 4) the driver also looks for a firmware file called "af35irtbl.bin" that >> comes from the "official" ITEtech driver (if it's not present the driver >> works anyway, but it prints an error message); >> >> I tested the driver with an Avermedia A867 stick (it's an OEM stick also >> known as the Sky Italia Digital Key with blue led: 07ca:a867) on a >> Ubuntu 10.04 system with kernel 2.6.32-38-generic-pae and the latest >> media_build tree installed. >> >> The good news: >> the driver loads properly, and, using Kaffeine, I could watch several >> channels with a small portable antenna; I could also perform a full >> frequency scan, finding several UHF and VHF stations. Signal strength >> and SNR reports works really well, and they seems to give a "realistic" >> figure of the signal quality (with both the portable and the rooftop >> antenna). >> When the stick is unplugged from the USB port, the driver unloads properly. >> >> The bad news: >> the driver seems to "lock" the application when it tries to tune a weak >> channel: in this cases, Kaffeine becomes unresponsive and sometimes it >> gives a stream error; for the same reason, the full scan fails to find >> all stations and takes a long time to complete. >> Also, when I tried to extract the stick from the USB port during one of >> this "freezing" periods, the system crashed :-( >> I reproduced this bug 3 times, and the last time I was able to see a >> kernel dump for a moment: the function that crashed the kernel was >> "af903x_streaming_ctrl". >> Neither of those issues are present with the Avermedia A867 original >> driver or Antti Palosaari's af9035 driver modified to support the A867 >> stick. >> >> I hope this feedback will be useful to improve the driver. >> >> Best regards, >> Gianluca Gennari > > Gianluca, > > thanks very much for your comments and patches. I will try the patches over > the weekend. > > With respect to your comment about the locking: I suspect this is because I > have used quite a lot of mutex locks. In particular the dual tuner stick > behaves very sensitive to any code changes and I have fought for months (no > joke) to get it working reasonably well (besides the bad reception problems). > A lot of the complexity in the driver is for the dual tuner and to support the > diversity feature. Hi Hans, I'm not an expert on this kind of problems, so take this further comments with a grain of salt. I see you always use mutex_lock(), while both the it913x driver and Antti's af9035 driver are often using mutex_lock_interruptible() and returning -EAGAIN when the lock request is interrupted. Could this be the reason of the kernel crash when the stick is unplugged from the USB port? Moreover, you are requesting a mutex lock even for functions that are just reading a bunch of registers (for example, to get the status or the SNR/signal strength values). Is this really necessary? I guess this is what is making Kaffeine unresponsive while the driver is struggling to tune a weak channel. Finally, I noticed that af903x_set_bus_tuner() is just setting up the tuner_desc data structure. Is a mutex_lock really necessary in this function? A possible small bug: af903x_streaming_ctrl is always returning 0. I think it should be returning "ret" in case of errors. > As to the af35irtbl.bin firmware: this is something I just copied from previous > drivers. I will probably just throw it out, because, as you also saw, it is > not needed (only needed for the HID mode of the remote control). > > Thanks very much for your input! > > Regards, > > Hans-Frieder Vogt e-mail: hfvogt <at> gmx .dot. net > Thank you for your effort. Regards, Gianluca -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
