Why can't I run a fglrx and a mesa/radeon X server at the same time?

[nanonyme]

then I don't understand why I need to specify which driver I want to load (radeon or fglrx). If only one driver can exist on a system, shouldn't the XServer just query the kernel for which driver is currently loaded?

I don't think there are interfaces for that for the very simple reason that a single piece or hardware is only supposed to have one driver

[agd5f]

then I don't understand why I need to specify which driver I want to load (radeon or fglrx). If only one driver can exist on a system, shouldn't the XServer just query the kernel for which driver is currently loaded?

In the early days of X, X drivers lived in userspace because they did not use DMA or interrupts. So X handled device enumeration and driver loading itself. As hardware features progressed, hw needed proper kernel drivers to support the full functionality. X drivers no longer touch hw directly, but rather communicate with the kernel driver. However, X still handles device enumeration and driver loading so you can still load an X driver that is compatible with the active kernel driver.

[profoundWHALE]

I don't think there are interfaces for that for the very simple reason that a single piece or hardware is only supposed to have one driver

It'd be really nice if I could just 'flip a switch' and xserver would restart and I would have fglrx running- no need to uninstall/reinstall when going back and forth.

I want to know if it's possible to have them both installed (of course, separate from each other) and just tell xserver which one that I want to be loaded? (This might have been answered but honestly I get lost fairly quickly sometimes.)
I guess I want to know A: if it can be done and B: if it would be worth it

To me, I think it would be more effective to just be running a hybrid kernel so that I can install a kernel driver and not have to reboot. That being said, I think I'm starting to head into the following territory, which is monolithic with userland drivers vs kernel in userland with kernel drivers. From my understanding, both will have roughly the same performance, the difference being with a monolithic kernel you could have kernel drivers which should provide faster overall performance and the kernel in general will just have less overhead and therefore perform better. So basically:

[Microkernel[Kernel + Drivers[Userland]]]
[Monolithic kernel[Drivers + Userland]]
And if I'm right so far, then Linux is like this
[Monolithic kernel + Drivers[Userland]]

I'd be welcome to anyone who can say that I have no idea what I'm talking about because in all honesty I really have no idea as to if I have a clue or not. Although I'd be pretty stoked if someone could confirm whether or not I'm on the right track.

[agd5f]

It'd be really nice if I could just 'flip a switch' and xserver would restart and I would have fglrx running- no need to uninstall/reinstall when going back and forth.

I want to know if it's possible to have them both installed (of course, separate from each other) and just tell xserver which one that I want to be loaded? (This might have been answered but honestly I get lost fairly quickly sometimes.)
I guess I want to know A: if it can be done and B: if it would be worth it

A. Yes, it could be done. Just about anything is possible with enough software.
B. It's not worth it.

[mao_dze_dun]

It sure would be nice, especially considering that half of the games run better with the open source driver. Not to mention a number of graphical glitches I encounter with fglrx.

[bridgman]

I guess the question is where you would rather see the effort go :

a) changing both driver stacks to allow switching back and forth on the fly

b) making the open drivers good enough that you can live without switching

My vote is (b).

[geearf]

I guess the question is where you would rather see the effort go :

a) changing both driver stacks to allow switching back and forth on the fly

b) making the open drivers good enough that you can live without switching

My vote is (b).

Absolutely!

[nanonyme]

It's most likely not safe to do it anyway as GPU is not reset to cold boot state on kernel driver unload. Agh, is this forum seriously now so broken mobile users have to top-post?

It'd be really nice if I could just 'flip a switch' and xserver would restart and I would have fglrx running- no need to uninstall/reinstall when going back and forth.

I want to know if it's possible to have them both installed (of course, separate from each other) and just tell xserver which one that I want to be loaded? (This might have been answered but honestly I get lost fairly quickly sometimes.)
I guess I want to know A: if it can be done and B: if it would be worth it

To me, I think it would be more effective to just be running a hybrid kernel so that I can install a kernel driver and not have to reboot. That being said, I think I'm starting to head into the following territory, which is monolithic with userland drivers vs kernel in userland with kernel drivers. From my understanding, both will have roughly the same performance, the difference being with a monolithic kernel you could have kernel drivers which should provide faster overall performance and the kernel in general will just have less overhead and therefore perform better. So basically:

[Microkernel[Kernel + Drivers[Userland]]]
[Monolithic kernel[Drivers + Userland]]
And if I'm right so far, then Linux is like this
[Monolithic kernel + Drivers[Userland]]

I'd be welcome to anyone who can say that I have no idea what I'm talking about because in all honesty I really have no idea as to if I have a clue or not. Although I'd be pretty stoked if someone could confirm whether or not I'm on the right track.