On 02/01/2010 07:28 PM, Jiri Kosina wrote: > On Mon, 1 Feb 2010, Pekka Sarnila wrote: >> Well short answer is: No, it does not work.
Hi, thanks for the input. >> What I did: >> >> I pulled few days ago latest >> >> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git >> >> and compiled it. Everything works fine including the tv-stick and the >> remote. However I get: >> >> <3>af9015: command failed:255 >> <3>dvb-usb: error while querying for an remote control event. Yes, I saw this quite recently too. For me it appears when it is booted up with the stick in. It's still to be fixed. >> I applied the patch in your mail and recompiled. Remote does not work; >> af9015.c gets no key presses. Instead that above message still comes. Yeah, and that's the reason why it doesn't work. >> Also removing the device or rmmod:ing dvb-usb-af9015.ko causes kernel oops. Already fixed: http://patchwork.kernel.org/patch/74095/ >> Analysis: >> >> When it works, the remote is recognized by the system as a HID-keyboard, >> and thus it works as a normal USB-keyboard. dvb-usb-remote.c is not >> participating at all (though it gives those errors). Actually it is. But it fails to get status. >> The remote is visible to the system as a usb interrupt end point. >> Interrupt endpoint tells the system the polling interval (by endpoint >> report). From the USB specs on the interval: >> >> The USB System Software will use this information during configuration >> to determine a period that can be sustained. The period provided by >> the system may be shorter than that desired by the device up to the >> shortest period defined by the USB (125 µs microframe or 1 ms frame). >> The client software and device can depend only on the fact that the >> host will ensure that the time duration between two transaction >> attempts with the endpoint will be no longer than the desired period. >> >> As I understand it, in plain English it means that the polling interval >> must not be longer than what the endpoint report says (in case of >> full-speed endpoint 1 to 255 ms). This device in question, assuming it >> gives the interval in full-speed mode even it really is high-speed >> device, gives 16ms interval period. >> >> However af9015.c/dvb-usb-remote.c accesses it as if it was a bulk >> endpoint and with 150ms interval. I did not look further on if this is >> the only reason or the reason for it not to work. But at least it is in >> clear contradiction of the USB-specs. To what statement is it in contradiction? The statement above is for interrupt transfers. >> I suspect, to make it work, much of the code from hid-driver should be >> copied to the device driver. Which code? I see no code being copied. >> However I think that would be exactly the >> wrong way to go. I think the whole idea of making for every device a >> separated driver ignoring the common code already in the kernel is bad >> architecture. Common code does not work well here. Don't you see weird key repetitions and similar? >> I have noticed more and more of this type of movement in >> the driver development resulting the same thing done in hundred >> different ways when common code could be used. Especially bad I think it >> is in the cases where universal specification is available (albeit there >> are many devices that do not follow the usb specs correctly). In this case I suppose this is why dvb-usb-remote exists. Maybe it can be handled better by a separate driver (still) as a part of the HID layer nowadays. Patrick, Johannes, why was not dvb-usb-remote implemented rather as a part of the HID layer? >> Also it is wrong idea that you could/should detect the type of remote >> controller based on the tv-stick. E.g with Haupauge TV-NOVA nearly any >> remote works ok (e.g my panasonic tv remote). Every generic ir-receiver >> sends also the manufacturer and model codes. Remote ir-to-code >> translates should be based on that (there is a kind of generic layer for >> that in linux kernel) and not on the tv-stick model at all (as in the >> af9015 driver). Sorry, I don't understand this paragraph. Could you rephrase? >> BTW I now recall how I got Afateck remote work as should. The driver >> loads ir-to-code translate table to the stick. I changed the codes to >> what made more sense. Why you didn't push this upstream? >> One problem here is that current HID layer is very sparse in the >> information it passes on, really only a code. It should also convey the >> precice id of the device so upper layer would be better able to deal >> with events. One of my hobbies is flight simulator flying. I use X-plane >> (excellent program). There is also a linux version. But the linux >> joystick driver is far from adequate for it (also some joysticks, yokes >> and pedals or some of their controls didn't work at all). So I use a >> special kernel for which I rewrote big parts of the HID-driver and >> input-driver and wrote completely new joystick driver. Now it works >> quite decently. One problem is the kernel->user joystick driver >> interface, but it can not be changed since that's what X-plane (and >> others use). One thing I got to change for that was that HID does less >> model specific processing and passes more event info to higher layer >> without breaking the old HID-devices (same with the input layer), so >> that the joystick layer could do more intelligent processing. I fixed >> also some bugs and one design omission in the HID driver (e.g. some >> force feedback joysticks uses that HID-specification, in standard kernel >> there is some ad-hoc code for that purpose). Can't be HID bus with a specific driver used instead now? -- js suse labs -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
