DVB USB stream parameters

DVB USB stream parameters

[Antti Palosaari]

What are preferred BULK stream parameters, .count and .buffersize?

for USB2.0?
for USB1.1?

buffersize, which is URB size, have great effect to system load. For 
example 512 bytes generates about 10x more wakeups than 5120. It is 
quite clear that 512 is too small for whole DVB stream. I did some test 
and looks like all USB2.0 devices I have here allow x512 or x188 sizes.
Heinrich Langos did some measurements and results can be seen here:
http://www.linuxtv.org/wiki/index.php/User:Hlangos

In my understanding we should found some balance between URB size and 
transferred stream bandwidth. For example DVB-T stream, when common 
transmission parameters are used, is more than 20Mbit/sec.

There is also USB bridge chips which does have two or more different 
standard frontends needed different stream bandwidths.

Should we add new module param for override module default?

a800        BULK  7x 4096= 28672
af9005      BULK 10x 4096= 40960 USB1.1 BUGFIX: x512=>x188
af9015      BULK  6x 3072=  3072 BUGFIX: x512=>x188
anysee      BULK  8x  512=  4096
ce6230      BULK  6x  512=  3072
cinergyT2   BULK  5x  512=  2560
cxusb       BULK  5x 8192= 40960
cxusb       BULK  7x 4096= 28672
dib0700     BULK  4x39480=157920 210x188 !!HUGE!!
dibusb-mb   BULK  7x 4096= 28672  56x512
dibusb-mc   BULK  7x 4096= 28672
digitv      BULK  7x 4096= 28672
dtt200u     BULK  7x 4096= 28672
dtv5100     BULK  8x 4096= 32768
dw2102      BULK  8x 4096= 32768
gl861       BULK  7x  512=  3584
gp8psk      BULK  7x 8192= 57344
m920x       BULK  8x  512=  4096
m920x       BULK  8x16384=131072 256x512 !!HUGE!!
nova-t-usb2 BULK  7x 4096= 28672
opera1      BULK 10x 4096= 40960
umt-010     BULK 10x  512=  5120
vp702x      BULK 10x 4096= 40960
vp7045      BULK  7x 4096= 28672

au6610      ISOC  5 frames 40 size 942
ttusb2      ISOC  5 frames  4 size 942

regards
Antti
-- 
http://palosaari.fi/

Re: DVB USB stream parameters

[Patrick Boettcher]

Hi Antti,

sorry for answering with delay.

On Sat, 5 Sep 2009, Antti Palosaari wrote:

> What are preferred BULK stream parameters, .count and .buffersize?
>
> for USB2.0?
> for USB1.1?
>
> buffersize, which is URB size, have great effect to system load. For example 
> 512 bytes generates about 10x more wakeups than 5120. It is quite clear that 
> 512 is too small for whole DVB stream. I did some test and looks like all 
> USB2.0 devices I have here allow x512 or x188 sizes.
> Heinrich Langos did some measurements and results can be seen here:
> http://www.linuxtv.org/wiki/index.php/User:Hlangos
>
> In my understanding we should found some balance between URB size and 
> transferred stream bandwidth. For example DVB-T stream, when common 
> transmission parameters are used, is more than 20Mbit/sec.
>
> There is also USB bridge chips which does have two or more different standard 
> frontends needed different stream bandwidths.
>
> Should we add new module param for override module default?
>
> a800        BULK  7x 4096= 28672
> af9005      BULK 10x 4096= 40960 USB1.1 BUGFIX: x512=>x188
> af9015      BULK  6x 3072=  3072 BUGFIX: x512=>x188
> anysee      BULK  8x  512=  4096
> ce6230      BULK  6x  512=  3072
> cinergyT2   BULK  5x  512=  2560
> cxusb       BULK  5x 8192= 40960
> cxusb       BULK  7x 4096= 28672
> dib0700     BULK  4x39480=157920 210x188 !!HUGE!!
> dibusb-mb   BULK  7x 4096= 28672  56x512
> dibusb-mc   BULK  7x 4096= 28672
> digitv      BULK  7x 4096= 28672
> dtt200u     BULK  7x 4096= 28672
> dtv5100     BULK  8x 4096= 32768
> dw2102      BULK  8x 4096= 32768
> gl861       BULK  7x  512=  3584
> gp8psk      BULK  7x 8192= 57344
> m920x       BULK  8x  512=  4096
> m920x       BULK  8x16384=131072 256x512 !!HUGE!!
> nova-t-usb2 BULK  7x 4096= 28672
> opera1      BULK 10x 4096= 40960
> umt-010     BULK 10x  512=  5120
> vp702x      BULK 10x 4096= 40960
> vp7045      BULK  7x 4096= 28672
>
> au6610      ISOC  5 frames 40 size 942
> ttusb2      ISOC  5 frames  4 size 942

I don't know exactly why (the USB/HW background for that is not present in 
my brain), but at some point having less than 39480B for one (high-level) 
URB for the dib0700 resulted in never having any URB returning from the 
USB stack. I chose 4 of them because .. I don't remember. It seems even 1 
is working.

I remember someone telling me that this is due to something in the 
firmware. I need to wait for some people to be back from whereever they 
are to know exactly what's going on (that's why I haven't responded yet).


--

Patrick 
http://www.kernellabs.com/

Re: DVB USB stream parameters

[Soeren Moch]

> I don't know exactly why (the USB/HW background for that is not 
> present in my brain), but at some point having less than 39480B for 
> one (high-level) URB for the dib0700 resulted in never having any URB 
> returning from the USB stack. I chose 4 of them because .. I don't 
> remember. It seems even 1 is working.

I vote for a single high-level URB. Besides the memory savings this is 
the only way I could get my nova-td stick working.
(see this thread: 
http://www.mail-archive.com/linux-media@vger.kernel.org/msg06376.html ) 
The patch runs flawlessly
on my vdr system for months now.

> I remember someone telling me that this is due to something in the 
> firmware. I need to wait for some people to be back from whereever 
> they are to know exactly what's going on (that's why I haven't 
> responded yet).
I hope you can sort out the dib0700_streaming_ctrl problems...

Soeren