Originally posted by agd5f
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All opinions are my own not those of my employer if you know who they are.
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Originally posted by Ericg View PostAlex does the PLL sharing affect the performance? Or is Radeon just not good at multi-monitor at this point? Or is the driver (not sure if its RadeonSI or R600g) for the 6950 just not as close to Catalyst for FPS? Just trying to figure out the numbers gap between Radeon and Catalyst on some of these benchmarks
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Originally posted by agd5f View PostYou can save bandwidth by doing pageflips rather than blit for buffer swaps, but at the moment, the open source drivers don't support non-vsynced pageflipping due to limitations in the xserver.## VGA ##
AMD: X1950XTX, HD3870, HD5870
Intel: GMA45, HD3000 (Core i5 2500K)
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Originally posted by agd5f View PostPLLs don't affect gfx performance. Having a huge desktop does however. Not only are you rendering to a much larger surface, you have more contention in the memory controller for bandwidth (display controllers and the gfx hardware). You can save bandwidth by doing pageflips rather than blit for buffer swaps, but at the moment, the open source drivers don't support non-vsynced pageflipping due to limitations in the xserver. When you are rendering to huge buffers you also tend to run out of vram so buffers may end up ping-ponging between vram and system memory from frame to frame. Improving the buffer placement heuristics in the open source driver would probably help a lot in vram limited cases.
1) Is a the 'non vsynced pageflipping' issue present on Wayland?
2) Will 'ping-ponging' be an issue on HSA systems? AMD CPU with an AMD dedicated card. I haven't checked out the HSA spec so I don't know if you can request to be put on graphics RAM vs system RAM or if you really are just saying "I need a buffer with xyz size" and get given back a pointer and youre blind to whether or not its on DDR3 ( / 4) or GDDR5. Just a thought that came up, figured I'd throw it in hahaAll opinions are my own not those of my employer if you know who they are.
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Originally posted by agd5f View PostAMD GPUs only have two PLLs which means we can only support two independent non-DP clocks. If you want to use more than two monitors, the additional monitors have to be DP. If you try again with 2 DVI/HDMI and 2 DP monitors it should work. Catalyst enforces this requirement. On radeon we allow PLL sharing where it's possible (e.g., multiple panels with the same clock) which is why it works there. That has it's own limitations however. E.g., if you try and change to a configuration that requires more than two PLLs, the modeset will fail.
http://www.anandtech.com/show/7400/t...eat-asus-xfx/3
One side question: Does open source radeon driver support 4K display now?
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Originally posted by darkbasic View PostWhich ones? Afaik Intel already does Async Display Flipping thanks to DRI3.
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Originally posted by agd5f View PostThat requires dri3 and present support. The problem in pre-dri3 land is that the xserver doesn't make the swap interval available to the driver so they can decide whether they want to flip or swap. There have been several attempts to fix it, but nothing has ever made it upstream.All opinions are my own not those of my employer if you know who they are.
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Originally posted by lovenemesis View PostHere's some more reading backing what agd5f saying.
http://www.anandtech.com/show/7400/t...eat-asus-xfx/3
One side question: Does open source radeon driver support 4K display now?
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