Fedora 21 Drops Support For A Bunch Of Old GPUs

[Ericg]

Using VESA drivers is the very definition of not having support. It's not that your card will not work at all, but it will use a highly generic, unaccelerated driver.

I think he meant this: http://www.phoronix.com/scan.php?pag...tem&px=MTI4NTU

[gQuigs]

I think he meant this: http://www.phoronix.com/scan.php?pag...tem&px=MTI4NTU

Indeed. The VESA driver we currently use is User Mode Set. I want them to be able to drop UMS entirely...

[AdamW]

Indeed. The VESA driver we currently use is User Mode Set. I want them to be able to drop UMS entirely...

There is a generic userspace modesetting driver called xorg-x11-drv-modesetting , these days. For any bit of hardware which has an in-kernel KMS driver but no specific userspace driver, this will be used as the fallback driver; this is already the case for some of the hardware mentioned, IIRC.

[bridgman]

Indeed. The VESA driver we currently use is User Mode Set. I want them to be able to drop UMS entirely...

IIRC the problem with KMS VESA is that with a straightforward implementation you end up having to execute real mode BIOS code in the kernel.

It would presumaly be possible to create a sufficiently robust "sandboxed" x86 emulator (and maybe something like QEMU is there today) for this to be considered safe but I haven't heard about anyone looking into it.

[mrugiero]

IIRC the problem with KMS VESA is that with a straightforward implementation you end up having to execute real mode BIOS code in the kernel.

It would presumaly be possible to create a sufficiently robust "sandboxed" x86 emulator (and maybe something like QEMU is there today) for this to be considered safe but I haven't heard about anyone looking into it.

Running an x86 emulator for an already non-accelerated driver doesn't sound like a decent performing solution, anyway.

[bridgman]

Running an x86 emulator for an already non-accelerated driver doesn't sound like a decent performing solution, anyway.

The only saving grace is that IIRC the BIOS calls (and hence the emulation overhead) would only apply to startup and mode switches. The performance critical bits (eg blitting from shadowfb to display memory) would run on the real CPU anyways.

[Ericg]

The only saving grace is that IIRC the BIOS calls (and hence the emulation overhead) would only apply to startup and mode switches. The performance critical bits (eg blitting from shadowfb to display memory) would run on the real CPU anyways.

Which is great. But there's a bit of a problem here...

If you have a new CPU, then the drivers for the GPU are solid and available thanks to AMD and Intel's work.
If you have an old CPU that doesn't have integrated graphics, and an old graphics card you are trying to run wherein you would need KMS VESA... your CPU probably cant handle doing everything it needs to AND all the stuff the GPU cant.

So the CPU's that CAN handle doing everything themselves, dont NEED TO. And the CPU's that NEED TO, CANT.

[torsionbar28]

While i'm generally against pulling out drivers for hardware, no matter how old, I think it's justified in this case. I don't know about Fedora, but at least with RHEL, it requires a PAE-enabled machine to install on. That means Pentium Pro and later. And that means you've got PCI bus at a minimum. Nobody uses VGA these days, everything is DVI (and HDMI) so it makes sense to drop support for cards that never came equipped with DVI ports. Radeon 7000, or Riva TNT2, or others from the late 90's all had DVI ports. So I can't imagine that dropping support for these crufty old non-DVI equipped chip sets is going to affect anyone. If you are using a Matrox Millenium, or Trident, or S3, it's time to toss it and replace with a $5 Radeon 7000 from ebay.

[Ramiliez]

Fedora is not kind of distro that runs everywhere for example on AMD C-70 Fedora 19 would not boot but Kubuntu worked OOTB

[Luke]

Not about to discard 1080p monitor because it only has VGA input

While i'm generally against pulling out drivers for hardware, no matter how old, I think it's justified in this case. I don't know about Fedora, but at least with RHEL, it requires a PAE-enabled machine to install on. That means Pentium Pro and later. And that means you've got PCI bus at a minimum. Nobody uses VGA these days, everything is DVI (and HDMI) so it makes sense to drop support for cards that never came equipped with DVI ports. Radeon 7000, or Riva TNT2, or others from the late 90's all had DVI ports. So I can't imagine that dropping support for these crufty old non-DVI equipped chip sets is going to affect anyone. If you are using a Matrox Millenium, or Trident, or S3, it's time to toss it and replace with a $5 Radeon 7000 from ebay.

No way in hell I am going to buy new monitors over the VGA port issue. I have the resolution I need, and I don't need a touchscreen or watch 3d movies. I've got two monitors on my AMD FX-8120/Radeon 6750 primary machine: One is a full 1080p primary monitor, one an older 1280 x 1024 secondary monitor. Both have only VGA inputs. One (the 1080p) is run with a DVI to VGA adapter..

I have found that to run gnome-shell or Cinnamon and get the menu to work right(on either) requires the power of at least a Radeon 4350 on the current Mesa driver. I dropped one of those into a board holding an old Athlon 64 at 2.3 GHZ. With Linux 3.12, Xorg-edgers, and Cinnamon over Ubuntu 3.10, that machine has a snappy desktop, just slightly slow menus-and thanks to UVD support can play a full 1080p video at 40% CPU. Yes, old junk with one core can be made to play 1080p video, I have finally answered that one.

For a Pentium 4 2GHZ machine that in 2008 was snappy with GNOME2, the best AMD card I could personally find for its AGP slot was a Radeon X1650. This could ALMOST run Cinnamon, but the menus were very slow and it could not run any composited desktop and play a 720p video at the same time. I don't have any old AGP cards in r600 or later architectures. As a result, it seems to me that you need a PCI-E slot or good on-chip graphics, not just a PCI slot to get good results with fat modern desktops.

As for video cards in legacy PCI, that requires a lot of extra CPU for the memory copy operations to copy from system ram to video ram. In an extreme case I saw Xorg using 50% CPU while playing a 640x480 video on a 450MHX Pentium 3, not leaving enough for the video to keep up. Remove the PCI video card card (an old one using the Mach64 driver) and run the onboard video, (which also used the Mach64 diver but had only 4MB of side-channel RAM), and the video would almost keep up, with Xorg using about 35% CPU or less and the video the rest. That was 15% of a 450 MHZ CPU as the additional load to handle the extra memory copy operations required by a PCI video card when loaded by video in XV.

My conclusion is this: If the old drivers are to be dropped by distros, and especially if the "mega-driver" format coming for Mesa is to follow suit, some way to install them needs to be kept around, even if it means custom-compiling mesa and dumping the whole mess into /usr/local. I would not want to see first Red Hat, then other distros not only drop older drivers but then configure Xorg/other display servers in such a way that they cannot be reinstalled. At the very least, current distros targetting older machines such as Mint/MATE need to be able to pull in drivers for older chipsets. Remember, there are people using all kinds of old junk-even Pentium 3's-as everything from file servers to print servers to public Internet access computers. Not all computers are gamers or workstations, and not everyone has an Ebay account.