Mauro Carvalho Chehab wrote: > Hi Jean, > > Jean Delvare wrote: >> Hi Andrzej, >> >> Last year, you submitted a fix for the cx88 remote control not behaving >> properly on some cards. The fix works fine for me and lets me use my >> remote control, and I am very grateful for this. >> >> However, I have noticed (using powertop) that the cx88 driver is waking >> up the kernel 1250 times per second to handle the remote control. I >> understand that it is needed for proper operation when the remote >> control is in use. What I do not understand is why it still happens >> when nobody uses the remote control. Even when no application has the >> event device node opened, polling still happens. >> >> Can't we have the cx88 driver poll the remote control only when the >> device node is opened? I believe this would save some power by allowing >> the CPU to stay in higher C states. > > The IR can be used even when nobody is opening the /dev/video device, as > it is an input device that can be used to control other things, including > the start of the video application. > > That's said, it makes sense to only enable the polling when the /dev/input/event > device is opened. > > Btw, the same polling logic is also present on bttv and saa7134 drivers. > > As I'm doing a large IR rework, with the addition of the IR core subsystem, > and the patch for handing the open/close is very simple, I've already wrote > a patch for saa7134, on my IR tree: > http://git.linuxtv.org/mchehab/ir.git?a=commitdiff;h=2b1d3acdb48266f05b82923b8db06e6c7ada0c72 > > The change itself is very simple, although I've added some additional checks > to avoid the risk of having an IRQ while IR is disabled. > > I have one cx88 board on my IR test machine (although I need to find the IR sensor for the > board I'm using there). If I find one that works, I'll try later to write a similar > code to cx88. > Btw, I found one sensor here and started working with it. With the new code, cx88 is generating lots of missing ticks. My IR debug log is full of those messages: [ 3276.764939] cx88[0] IR: Missed ticks 15 [ 3276.768999] cx88[0] IR: Missed ticks 3 [ 3276.772323] cx88[0] IR: Missed ticks 3 [ 3276.789027] cx88[0] IR: Missed ticks 15 [ 3276.793085] cx88[0] IR: Missed ticks 3 [ 3276.796409] cx88[0] IR: Missed ticks 3 [ 3276.813025] cx88[0] IR: Missed ticks 15 [ 3276.816347] cx88[0] IR: Missed ticks 3 [ 3276.816347] cx88[0] IR: Missed ticks 3 [ 3276.837011] cx88[0] IR: Missed ticks 15 [ 3276.840339] cx88[0] IR: Missed ticks 3 [ 3276.845028] cx88[0] IR: Missed ticks 3 [ 3276.861019] cx88[0] IR: Missed ticks 15 [ 3276.864342] cx88[0] IR: Missed ticks 3 [ 3276.869089] cx88[0] IR: Missed ticks 3 This doesn't seem right, especially since this test machine is in text mode, and there's nothing running there. -- Cheers, Mauro -- 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
