Wednesday, March 30, 2011

Maintaining the Linux device driver code base

After a (sadly) failed attempt to convert my significant other to Linux, I had a discussion with her about why it failed. Root cause.

Her computer works well with Windows, not at all with Linux. The reason is that her laptop will display no better than 800x600 resolution as there is no good SIS671 graphics driver for Linux (and there is for Windows). Nothing recent, functional, supported, viable or workable.

Why isn't there one for Linux?

Because it doesn't make money. Business is the process of converting time into money. Sales people get customers to buy a product or service. Technical people produce the products or deliver the services. Management and administration functions supported and enables the business to operate as a whole. (Or so the theory goes, but that is another story)

And because programmers also need a place to live. And to feed the kids.

There is cost involved – an investment, and there is a price, the return on the investment. A product, in this case a device driver for the graphics processor, needs to be designed, produced and supported. The technical people and the tools they need to do this do not come cheap.

Device drivers for Linux, however, does not make much, if any money for the companies involved. People do not pay for device drivers, rather they (rightly) expect it to be included in the cost of the hardware.

Even closed source Linux drivers are free – the vendor have to cover the costs through the sales of hardware. But the business model is flawed – The cost to deliver the Linux device driver far exceeds the income generated from hardware sales to Linux users. Thus this expense must be subsidised from sales to Windows users.

Unless the Linux user base grows to reach a critical mass, the point where enough Linux users buy the hardware to be able to justify the cost of the driver development and support, the situation will not change.

The above situation is the same, no, actualy worse for other hardware – Webcams, GPS'es, Cell-phones, USB thumb drives, bluetooth hardware, Wi-Fi and network cards, Fingerprint readers and touch-pad input devices. Every single bit of hardware.

The Linux kernel includes almost all device drivers for the hardware because of this situation. It is the only way the Linux community can use most of the consumer hardware available in the world today – that is, by developing the needed device drivers themselves.

As a result Linux supports much much more hardware than Windows does. Windows depends on the driver disks that ships with the hardware because Microsoft does not provide driver software for every bit of hardware out there!

The more you think about it, the more you realise just how unbalanced the situation really is! Microsoft sells its Windows operating system with only basic device drivers included – for proper functionality, features and performance, you need to load the hardware manufacturer's drivers. The hardware manufacturers provide the device drivers because otherwise they would lose the majority of their market – Windows users.

The Linux community, an entity that makes no money, needs to provide device drivers created through donated effort. I am aware of the exceptions, but that does not change the overall picture. The effort to maintain and update the base of device drivers included in the Linux kernel increases as the number of pieces of hardware to be supported increases. In other words: Every time a new piece of hardware appears in the shops.

To add insult to injury, the Linux community locks themselves in with the GPL license, which means they can not, for example, utilise and share effort by other Unix or BSD distributions because the Linux kernel enforces the use of the restrictive GPL.

Even worse, a Linux device driver works only on a specific release of the kernel. This is because the kernel interfaces for device drivers changes, and as a result the device driver needs to be re-compiled for every update, even minor updates, to the kernel. The amount of extra work this would place on hardware manufacturers to ensure that their device driver works on every kernel version is significant, and much more than what is needed for, for example, Windows or Solaris.

The long and the short of it is that to produce and maintain device drivers for Linux is prohibitively expensive, and the market loss as a result of not supporting Linux users is essentially negligible to most hardware manufacturers' bottomline!

Regarding the market share situation: I have long held the belief that through “allowing” us to copy Windows, Bill Gates got the world to using MS Windows. It is what most people grew up with on our computers at home, and what we as a result expected when we entered the workplace. More than just the majority of the work force, today's computer gamer is tomorrow's IT business decision maker.

But there is some light on the horizon: The Wayland Display Server may just give the Linux graphics stack the performance boost it needs to make it a viable gaming platform, which in turn will gain it the adoption of many gamers, and in the long run more market share on the desktop. Now if only Linus would fix the device driver ABIs and APIs to make it that bit easier for hardware manufacturers to support their device driver software on Linux...

There is a lot of fud on the net about how the "deliberately dynamic ABIs" of the Linux kernel makes Linux drivers better maintained, less buggy, etc. Sigh.

1 comment:

Movies Gallery 2011 said...

Excellent pieces. Keep posting such kind of information on your blog. I really impressed by your blog.
Vee Eee Technologies