Hi !
i just read up again on this: http://www.mail-archive.com/vdr@linuxtv.org/msg13224.html
Actually i think this would be also a good starting for
a) save some energy - if DVB devices are not opened all the time, the driver has the chance to put it into standby saving some heat, energy and lifetime of the cards
b) have a beginning of dvb device hotplug - if dvb devices are discovered on demand, its a good chance at a later stage to also add and remove cards on the fly. There is sure some notification required from udev to vdr so it can keep internal reference of the how many devices are there.
Not that i could help in doing this - being aware it might take a while until its finished - but i still thought to share my thoughts, that this addition is not only usefull for shared frontends, but also for general usage.
Hope the work on this is continued and possibly accepted by Klaus after some review and as work in progress.
Kind Regards
Steffen
On Sat, Dec 4, 2010 at 4:24 AM, Steffen Barszus steffenbpunkt@googlemail.com wrote:
a) save some energy - if DVB devices are not opened all the time, the driver has the chance to put it into standby saving some heat, energy and lifetime of the cards
There are a couple cards that consume a lot of power iirc so this could actually be useful for users of those cards. But what about performance/lag? And also how healthy is it to constantly put a device in and out of standby?
b) have a beginning of dvb device hotplug - if dvb devices are discovered on demand, its a good chance at a later stage to also add and remove cards on the fly. There is sure some notification required from udev to vdr so it can keep internal reference of the how many devices are there.
I wonder if this is actually useful. Is there anyone that would need/want this in the real world?
On 04/12/10 18:09, VDR User wrote:
On Sat, Dec 4, 2010 at 4:24 AM, Steffen Barszus steffenbpunkt@googlemail.com wrote:
b) have a beginning of dvb device hotplug - if dvb devices are discovered on demand, its a good chance at a later stage to also add and remove cards on the fly. There is sure some notification required from udev to vdr so it can keep internal reference of the how many devices are there.
I wonder if this is actually useful. Is there anyone that would need/want this in the real world?
I can imagine a situation where you're already recording one or more programmes with your internal card, then realise you want to watch/record something else on a different channel and you forgot to plug your USB receiver back in after you took it away to use with your laptop...
Am Sat, 4 Dec 2010 10:09:42 -0800 schrieb VDR User user.vdr@gmail.com:
b) have a beginning of dvb device hotplug - if dvb devices are discovered on demand, its a good chance at a later stage to also add and remove cards on the fly. There is sure some notification required from udev to vdr so it can keep internal reference of the how many devices are there.
I wonder if this is actually useful. Is there anyone that would need/want this in the real world?
In which world did you live the last months ;) ? Sorry, I couldn't insist.
Our VDR-Distribution yaVDR is optimized for a short boot. With old fashioned PCI cards you can get down to 6 seconds boot time since grub, but if one of our user decides to buy another p. e. usb device, we have to delay the boot up to 30 seconds to allow the usb device to get ready. With device hotplugging there would be no need to wait for this device and the user would already see tv 30 seconds earlier. Believe me there are users that thinks this matters.
Gerald
On Sat, Dec 4, 2010 at 11:37 AM, Gerald Dachs vdr@dachsweb.de wrote:
Am Sat, 4 Dec 2010 10:09:42 -0800 schrieb VDR User user.vdr@gmail.com:
b) have a beginning of dvb device hotplug - if dvb devices are discovered on demand, its a good chance at a later stage to also add and remove cards on the fly. There is sure some notification required from udev to vdr so it can keep internal reference of the how many devices are there.
I wonder if this is actually useful. Is there anyone that would need/want this in the real world?
In which world did you live the last months ;) ? Sorry, I couldn't insist.
Our VDR-Distribution yaVDR is optimized for a short boot. With old fashioned PCI cards you can get down to 6 seconds boot time since grub, but if one of our user decides to buy another p. e. usb device, we have to delay the boot up to 30 seconds to allow the usb device to get ready. With device hotplugging there would be no need to wait for this device and the user would already see tv 30 seconds earlier. Believe me there are users that thinks this matters.
I'm a fan of short boot times. Are there that many users that are power cycling their pc's frequently? Of all the pc's I use be them Windows or Linux, work or personal, hardly any of them are rebooted. Really only my test boxes (which are intended) or in the event of a power loss or so due to very bad weather. Of course that's just my usage and everybody has their own. I just don't see that this is a situation that's even remotely common.
I'm not for or against the idea. I just wonder if there's significant need to distract Klaus away from other things people have been needing/wanting for quite a long time.
On Sat, 4 Dec 2010 10:09:42 -0800 VDR User user.vdr@gmail.com wrote:
On Sat, Dec 4, 2010 at 4:24 AM, Steffen Barszus steffenbpunkt@googlemail.com wrote:
a) save some energy - if DVB devices are not opened all the time, the driver has the chance to put it into standby saving some heat, energy and lifetime of the cards
There are a couple cards that consume a lot of power iirc so this could actually be useful for users of those cards. But what about performance/lag? And also how healthy is it to constantly put a device in and out of standby?
Actually how likely it would be that this is constantly happening ? Having 2 or 3 tuner watching 1 single channel, then every now an then a couple of recordings i think it's likely 80% in standby - similar to harddisks which i have in standby except i watch recordings etc.
b) have a beginning of dvb device hotplug - if dvb devices are discovered on demand, its a good chance at a later stage to also add and remove cards on the fly. There is sure some notification required from udev to vdr so it can keep internal reference of the how many devices are there.
I wonder if this is actually useful. Is there anyone that would need/want this in the real world?
I think yes, beside what gerald mentioned allready, one could also think of driver reload on a single device without interrupting running recordings. Also there might be devices which ar not THAT standard like netceiver or Sundtek network shared devices, which dont work like you would expect from internal pci devices. So question is more what are the arguments against this except the required changes ? I think this would be what you would expect how it works in todays world.
One could say it's the reason why you can not have TV picture 2s after S3 keeping the vdr running during S3.
To make it short I see use cases for it - i just can not manage to do it myself - so i thought i share my thoughts, by chance someone interested is reading it.
Kind Regards
Steffen
On Sat, Dec 4, 2010 at 4:58 PM, Steffen Barszus steffenbpunkt@googlemail.com wrote:
a) save some energy - if DVB devices are not opened all the time, the driver has the chance to put it into standby saving some heat, energy and lifetime of the cards
There are a couple cards that consume a lot of power iirc so this could actually be useful for users of those cards. But what about performance/lag? And also how healthy is it to constantly put a device in and out of standby?
Actually how likely it would be that this is constantly happening ? Having 2 or 3 tuner watching 1 single channel, then every now an then a couple of recordings i think it's likely 80% in standby - similar to harddisks which i have in standby except i watch recordings etc.
My main vdr box has a few tuners. Aside of people watching live tv often, there are numerous daily timers pretty much for every day of the week. I had to disable spin-down on my recording drive because of this. It was simply getting hammered too much with spin-down/up. The same holds true for my dvb devices. I'd rather not hammer my devices with in/out standby mode at the chance of negligible savings. At the very least the user should have the option to enable/disable "power saving mode" or whatever you'll call it. I guess each user will have to decide if this is something he wants to use or not.
Another thing this patch should consider is card capabilities. If a certain transponder requires a certain card, is the patch smart enough to know that? An example of this is the mixture of transponders requiring 8psk turbo fec modulation, other transponders requiring qpsk turbo fec, and yet others using just plain qpsk. If qpsk turbo fec is needed but a device that only supports regular qpsk is powered up, that's useless.
On Sun, Dec 05, 2010 at 01:58:42AM +0100, Steffen Barszus wrote:
To make it short I see use cases for it - i just can not manage to do it myself - so i thought i share my thoughts, by chance someone interested is reading it.
Have a look at the mcli-plugin and the few patches for vdr it needs. It is already doing everything you are describing, as we needed that for the NetCeiver-streaming for multiple clients.
Namely:
a) Providing virtual tuners to allow arbitrary hotplugging (tuner types and sat positions) and even changing tuner properties "on-demand".
b) Disabling unused tuners, however this is hard in general as there's no hard information on the PID usage type available.
But be warned, hotplugging has some pitfalls ;) So the "resource allocation checks" for a point of time in the future (like timer collisions) are no longer useful.
-
Georg Acher -
Gerald Dachs -
Steffen Barszus -
Tony Houghton -
VDR User