Em Thu, 18 Sep 2014 08:22:33 -0300 Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx> escreveu: > Em Fri, 05 Sep 2014 11:34:01 +0300 > Antti Palosaari <crope@xxxxxx> escreveu: > > > Moikka Olli > > > > I ran some PM tests for that patch set, using PCTV 292e, which is em28xx > > + Si2168 B40 + Si2157 A30. Here is results: > > > > current impementation > > ------------------------------------- > > cold plugin 40 mA > > streaming 235 mA > > sleeping 42 mA > > > > si2157: change command for sleep > > ------------------------------------- > > cold plugin 40 mA > > streaming 235 mA > > sleeping 60 mA > > > > So it increases sleep power usage surprisingly much, almost 20mA from > > the USB, nominal 5V. > > > > It is also funny that you will not lose firmware for Si2168 when sleep > > with command 13, but that Si2157 tuner behaves differently. > > > > I think I will still apply that, it is just firmware download time vs. > > current use in sleep. > > IMHO, the best is to keep it saving more power. Ok, it will take more > time to wake up but so what? If someone is putting the machine to sleep, > it is because he/she wants to save power. > > So, IMHO, we should keep the default behavior as-is. Nothing prevents > that we would add a modprobe parameter or to use some other method that > would allow the user to choose between those two different ways. Sorry, I misunderstood this patch. There are actually two different things, each requiring a different PM setting: 1) to put the tuner to sleep while it is not in usage; 2) put the machine to suspend. This patch is for (1). That's FINE. I'll apply it. Yet, for (2), assuming a suspend to ram, the best is to save more power. In the past, the DVB core didn't make any distinction between those two, but we recently added a hook for suspend there. So, it makes sense to keep the tuner powerdown mode for suspend. Regards, Mauro. > > Regards, > Mauro > > > > > Antti > > > > > > On 08/25/2014 09:07 PM, Olli Salonen wrote: > > > Instead of sending command 13 to the tuner, send command 16 when sleeping. This > > > behaviour is observed when using manufacturer provided binary-only Linux driver > > > for TechnoTrend CT2-4400 (Windows driver does not do power management). > > > > > > The issue with command 13 is that firmware loading is necessary after that. > > > This is not an issue with tuners that do not require firmware, but resuming > > > from sleep on an Si2158 takes noticeable time as firmware is loaded on resume. > > > > > > Signed-off-by: Olli Salonen <olli.salonen@xxxxxx> > > > --- > > > drivers/media/tuners/si2157.c | 7 ++++--- > > > 1 file changed, 4 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/media/tuners/si2157.c b/drivers/media/tuners/si2157.c > > > index efb5cce..c84f7b8 100644 > > > --- a/drivers/media/tuners/si2157.c > > > +++ b/drivers/media/tuners/si2157.c > > > @@ -197,9 +197,10 @@ static int si2157_sleep(struct dvb_frontend *fe) > > > > > > s->active = false; > > > > > > - memcpy(cmd.args, "\x13", 1); > > > - cmd.wlen = 1; > > > - cmd.rlen = 0; > > > + /* standby */ > > > + memcpy(cmd.args, "\x16\x00", 2); > > > + cmd.wlen = 2; > > > + cmd.rlen = 1; > > > ret = si2157_cmd_execute(s, &cmd); > > > if (ret) > > > goto err; > > > > > > -- > 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 -- 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
