[mythtv-users] DVB-S2 PCI-express cards

Simon Hobson linux at thehobsons.co.uk
Fri Sep 30 15:18:05 UTC 2011

Emmanuel wrote:

>But I thought they would release the source code for the frontend blob,
>but this has yet to happen.

And is very unlikely to happen.

It's a standard problem that somewhere up the line someone won't 
release information in an open manner - typically it will be some 
level of hardware manufacturer. The normal situation is that to get 
the info you need to write good drivers (or even any drivers) you 
have to agree to non-disclosure restrictions. In other words, the (I 
believe in this case, chip) manufacturer will tell you the 
information but you aren't allowed to tell anyone else.

Thus it's not possible for TBS to release open drivers - hence the 
binary blobs. Or rather, they could - but then they'd get sued by the 
chip manufacturer, and well screw themselves by not being given 
access to such information in the future.

I have mixed views on this.

The idealist in me says this is a bad thing - the chip manufacturer 
shouldn't keep such information private, and the card vendor should 
make their drivers open.

The pragmatist in me says that it's better to have such binary 
drivers (provided it's done in a sensible way) than have no drivers 
at all.
I've less sympathy for the chip manufacturers since you can be fairly 
certain their competitors will get the programming information one 
way or another. But for TBS, there is also the issue that they don't 
want to do all the work in making an open driver - only for another 
manufacturer to come along, stick the same chips on a card, and 
profit from selling cards which use the open drivers but without the 
overheads (costs) of having written the drivers.

Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.

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