Re: [WIP]Raspberry Pi as USB HDMI-out (via USB Networking)
 

Hi
I came across this device.
http://www.win-star.com/eshop/goods.php?id=30
It has linux drivers too :)

it's around 100AUD new
http://www.tradingpost.com.au/Comput...er=AD004985904

Re: [WIP]Raspberry Pi as USB HDMI-out (via USB Networking)
 

Looks like the better idea if all we want from the raspberry is video output.

But thee might even be a cheaper and more common way to do that. Since 2010 there is a standard called MHL [1] with microUSB->HDMI adapters available from 15 Euros and it seems like at least in principle it works with Linux [2].
Does somebody know if kernel-power supports MHL or can be made to support it?

[1] http://en.wikipedia.org/wiki/Mobile_...efinition_Link
[2] http://patchwork.linuxtv.org/patch/9687/

Re: [WIP]Raspberry Pi as USB HDMI-out (via USB Networking)
 

The most important thing is that the drivers are open source, so that they can be compiled for our (ARM CPU) Linux kernel. If there are only closed-source Linux drivers available, then they're probably only for x86 (Intel / AMD CPUs) Linux.

Re: [WIP]Raspberry Pi as USB HDMI-out (via USB Networking)
 

There only one problem, N900 hasn't a MHL chip inside :D

Chip is not in the cable, it must be on the on-board logic

Re: [WIP]Raspberry Pi as USB HDMI-out (via USB Networking)
 

I suspected something like that but I was hoping it isn't true.

I found another disturbing problem in connection with the N900's USB port:
It seems to be limited to approximately 4.1MB/s.I tried that with a 2.5" external HDD, a USB key and an SD card in a card reader by copying 4kB and 1MB blocks directly from the block device via dd using HEN and KP49. So the results are unaffected by file system parameters. I know that each of the devices reaches at least 20MB/s on other computers.
My CPU was not the limiting element.
Can somebody please check these findings? If what I've found is true then USB is not our fastest interface to the outside world. It's WLAN.

Re: [WIP]Raspberry Pi as USB HDMI-out (via USB Networking)
 

Not sure, not really interested in get HDMI out of a phone RCA is good enough :)
I'm sure if someone interested emails them saying why you need the source they'll give it, or at least to a build for ARM.

I d/l the manual and it refers to: Libdlo & displaylink.
So i would say it's the drivers/application
http://libdlo.freedesktop.org/wiki

Re: [WIP]Raspberry Pi as USB HDMI-out (via USB Networking)
 

check powertop, for C-states
Also (if you have the expertise) check clock frequencies of the CPU<->musbcore and the musbcore<-ULPI->PHY interface

HEN-host for sure isn't the optimum implementation of a USB host, but it shouldn't be THAT lame. How much could you dump to N900 with /dev/null as destination?

/j

Re: [WIP]Raspberry Pi as USB HDMI-out (via USB Networking)
 

I will do that. What does it tell me in connection with USB transfer rates?

Unfortunately I do not have the expertise. Any hints on how to do that and how to interpret the results?
When it comes to kernel-related things I don't have much experience.

About the same 4.x MB/s

Re: [WIP]Raspberry Pi as USB HDMI-out (via USB Networking)
 

I ranand observed the C-states for about 10 minutes. The CPU was always in C0.

Re: [WIP]Raspberry Pi as USB HDMI-out (via USB Networking)
 

Even *if* results will turn out so bad, we can always use USB networking with Pi as host, and N900 as client, yep? At least, it would solve the transfer rate problem.

Nevertheless, it would be great to hammer hostmode transfer rates, for it's own sake. It's quite unbelievable, that no one else noticed it up to date... But, who knows. IF it's true, it's some kind of bug, not limitation of hostmode implementation (for N900) as whole, yep?
---

Maybe we should continue discussing hostmode transfer rate issues in hostmode thread (main one, not the "problems" section)?

/Estel