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drivers for the Synopsys USB controller in BCM2835 are [email protected]

Posted: Wed Aug 15, 2012 10:08 pm
by dan_in_sd
I read this today in the forum: "drivers for the Synopsys USB controller in the BCM2835 are a bit crap "

Issues in the R-Pi Forums that might be resolved with a better USB controller driver:
1. Stickey keys.
2. Poor USB thoughput when using a simple webcam (UVC) at anything higher then 352x288 resolution. (i.e. using 640x480 resolution or higher causes the image to become garbled or sections of the image are duplicated much like a kaleidoscope. This is something I'm battling right now with Raspian )
3. Poor throughput with USB Wi-Fi Network Adapters.
4. Problem with USB 3.0 devices. ( They are supposed to operate on USB 2.0 bus, but R-Pi owners are seeing issues with this. )
5. Keyboard lock-ups after high amounts of data was passed through the USB ports. And un-plugging and re-connecting the keyboard does not help. you have to power down the R-Pi and power up again.

The question is....Does the Raspberry Pi Foundation have enough muscle to ask for Synopsys to improve the controller driver?
( ... probably they cant do anything to improve any Synopsis bugs already in the SoC. but that would be excellent if they could. )

What it comes down to is this : "Lets get a rock-solid USB controller & driver before everyone wishes they hadnt bought a RasPi in the first place."


Re: drivers for the Synopsys USB controller in BCM2835 are c

Posted: Wed Aug 15, 2012 11:48 pm
by mung
I am not an expert and have no idea about anything to do with USB or how the BCM2835 implements it, so really have no place saying anything about the USB issues.

But I like to suggest that if issues are important to you, YOU should do some research and ask relevant experts what YOU can do to help. I don't like to say the RPI is in pre release and the foundation are using present users as free developers and beta testers, but that is what they are doing, and I don't think you can blame them as the foundation is not making a profit from its work.

Why not ask what software you need to produce bug reports (dmesg, lsusb, cat /proc/usb?? ).

After you have submitted your problems start looking at the kernel source code yourself, start by compiling a standard kernel from the RPI repository then look at adding extra debugging symbols etc... You may not think you can be any use but you should at least try, as you will learn a lot from the attempt.

Of course I have done some work on this using a ouijah board and my own personal opinion favours the possibilty that some extra power storage capacitors are required near the LAN9512 chip (thats what the voices told me).

I hope someone can put more time and effort into fixing this problem than I have :D

Re: drivers for the Synopsys USB controller in BCM2835 are c

Posted: Thu Aug 16, 2012 12:43 am
by dan_in_sd
@mung : thanks. but i did all the dmesg...lsusb....tail -f syslog i want to do. I know the R-Pi is community supported, but I just want a cheap webcam thats UVC compatible to work OOB with my R-Pi running Raspian. And not have to deal with all this low-level kernel driver stuff.

Besides, dealing with debug versions of kernels and drivers is tough work to do completely alone and not get paid for any of it.

You mentioned 'extra power storage capacitors' near the LAN IC. Do you mean for filtering (decoupling) of the LAN IC itself? Or do you mean the caps that supply the 5Vdc power on the USB ports , C30 thru C33, those caps?

Note: Info on the Synopsys USB Core that Broadcom choose for the BCM2835 is here: ... 2_0_hs_otg

Re: drivers for the Synopsys USB controller in BCM2835 are c

Posted: Thu Aug 16, 2012 1:16 am
by dan_in_sd
Yeah, perhaps im barking up the wrong tree here. And perhaps its just electrical design problem like mung eluded to in his/her post. But then again.... what if it is a problem with the Synopsys USB core and/or kernel driver? What if the problem is serious and no one can fix it? What if......

:o Well look at what I just found. Others over at Element14's community site are having a similar USB difficulty. Read on..... ... read=19436

Re: drivers for the Synopsys USB controller in BCM2835 are c

Posted: Thu Aug 16, 2012 1:47 am
by jamesh
Yes there are problems with the driver. They are being worked on, as you would have known had you read the already existibg thread on the subject. closing this thread as a duplicate.