How good can the DRI drivers be?

[WalmartSniperLX]

I have a Radeon 9250 PCI card and I cannot get fglrx working because of the hassle with the fact that AMD/ATI discontinued support for my gpu with new driver releases. The latest driver compatible is 8.28.8 and it doesn't want to work with my kernel 2.6.20 (FC6) and I don't feel like going thru the hassle to patch since I feel as if the performance is better with the open source driver with this gpu (based on my real-life tests when running Ubuntu 6.06 with kernel 2.6.16). Would I be correct in saying this? How good can the DRI radeon drivers be and how can I tweak them to the best?

[Michael]

I have a Radeon 9250 PCI card and I cannot get fglrx working because of the hassle with the fact that AMD/ATI discontinued support for my gpu with new driver releases. The latest driver compatible is 8.28.8 and it doesn't want to work with my kernel 2.6.20 (FC6) and I don't feel like going thru the hassle to patch since I feel as if the performance is better with the open source driver with this gpu (based on my real-life tests when running Ubuntu 6.06 with kernel 2.6.16). Would I be correct in saying this? How good can the DRI radeon drivers be and how can I tweak them to the best?

The DRI driver performs less than the fglrx driver. See: http://www.phoronix.com/vr.php?view=8656

For tweaking, see: http://dri.freedesktop.org/wiki/ATIRadeon#head-8851142da56fd885ce668a165b33fee7003e858d

[WalmartSniperLX]

The DRI driver performs less than the fglrx driver. See: http://www.phoronix.com/vr.php?view=8656

For tweaking, see: http://dri.freedesktop.org/wiki/ATIRadeon#head-8851142da56fd885ce668a165b33fee7003e858d

Thanks. As far as it performing less than fglrx, I would agree and disagree. I had an X1600pro in another pc using fglrx (8.34.x I think) that performed less than my mobile 9200 using the radeon driver. Its more gpu specific on which one performs better.

[WalmartSniperLX]

Jw but what is the difference between the DRI modes (0660, 0666, etc)?

[Michael]

It's for restricting who can access direct rendering. For all users, use 0666

[yoshi314]

the mentioned performance comparisons were for r300/r400 chipset, which is being reverse engineered even now.

the 9250 card has an r200 variant chipset (rv280). ati gave out full specs for r200, so i believe r200 support is quite good in the open driver.

the open drivers work quite well on this card.

[Michael]

Here's some older benchmarks from the Radeon 9250 with both drivers: http://www.phoronix.com/vr.php?view=6482

[WalmartSniperLX]

Ok so basically DRI support is low because they can only build off what ATI/AMD releases, which isn't everything for copyright protection?

Also, if this is the case, how do I know Im getting my money worth of performance with my chipset/cpu using the Linux modules/in kernel drivers? (I hope Im not going too off topic with this question)

[yoshi314]

hard to tell. but they're constantly improving. i wonder what will the introduction of TTM change in performance. besides, many things could have changed since those benchmarks were done in the open driver code.

my friend uses his 9600 agp card daily with open drivers and he doesn't have any complaints about performance, as far as i can tell.

[WalmartSniperLX]

What would be the best way to upgrade the open source driver?

[yoshi314]

upgrade? well, build mesa, new xorg-server (if an update is available) build x11-drm modules, and then build the driver.

since we're on the topic of the open drivers - this site really needs some attention for people interested in opensource ati drivers development :

http://tirdc.livejournal.com

maybe there will be some info on r500 sometime in the future. (jerome glisse recently gave a small r500 status update on dri-devel mailing list).

[Svartalf]

The DRI driver performs less than the fglrx driver. See: http://www.phoronix.com/vr.php?view=8656

Heh... That's not apples to apples. You're comparing the DRI driver R300-to-R300 and AMD's got a little of an edge on the DRI team there- beings that AMD understands the chip better. They don't understand Linux as well, unfortunately, so the driver is sub-par compared to Windows, which is, sadly, somewhat sub-par compared to NVidia. Now, the right way to do these comparisons is to do R200 to whatever... For SOME applications, the R200 support, because much more robust T&L support than the "comparable" R300 chips' support provided by the closed source drivers , will do better (MUCH BETTER) with an R200 with DRI than the closed source R300 answer.

Michael, I'd LOVE for you to do a review of the thing I just mentioned- or to let me do a guest write-up on the subject.

[Michael]

Heh... That's not apples to apples. You're comparing the DRI driver R300-to-R300 and AMD's got a little of an edge on the DRI team there- beings that AMD understands the chip better. They don't understand Linux as well, unfortunately, so the driver is sub-par compared to Windows, which is, sadly, somewhat sub-par compared to NVidia. Now, the right way to do these comparisons is to do R200 to whatever... For SOME applications, the R200 support, because much more robust T&L support than the "comparable" R300 chips' support provided by the closed source drivers , will do better (MUCH BETTER) with an R200 with DRI than the closed source R300 answer.

Michael, I'd LOVE for you to do a review of the thing I just mentioned- or to let me do a guest write-up on the subject.

We have done the R200 benchmarking in the past and the R200 could be added to the TODO list, which is very long as you may imagine.

We do also accept freelance articles at Phoronix.

[Svartalf]

We have done the R200 benchmarking in the past and the R200 could be added to the TODO list, which is very long as you may imagine.

We do also accept freelance articles at Phoronix.

I'm going to take that as a hint, then... :D

(I've got a bit of a todo list as well, so it might be a couple of weeks yet...)

[marcheu]

Yes, things have changed since then, and now the r200 DRI driver is on par, performance-wise, with the last releases of fglrx that had working r200 support (its image quality should be a bit better as well)

And yes, r200 DRI support is way better than r300 DRI support, comparatively (notice I'm not saying r200s are faster than r300s here, just that there's more left to optimize in the r300 dri driver).

If you want to get the maximal performance with the DRI drivers, you have to tweak things a bit, in particular I suggest you enable hyperz. There is a tool called driconf (which your distro probably packages) that lets you do that in a graphical fashion.