Messages in this thread | | | From | Ilia Mirkin <> | Date | Fri, 17 Nov 2017 14:37:36 -0500 | Subject | Re: Blank console but X11 works on MCP79 - old regression since 3.8 |
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On Fri, Nov 17, 2017 at 2:25 PM, Ondrej Zary <linux@rainbow-software.org> wrote: > On Friday 17 November 2017 18:41:17 Ilia Mirkin wrote: >> On Fri, Nov 17, 2017 at 12:33 PM, Ondrej Zary >> >> <linux@rainbow-software.org> wrote: >> > @@ -483,8 +483,8 @@ >> > nouveau 0000:02:00.0: disp: 0860: 00000000 -> 00000500 >> > nouveau 0000:02:00.0: disp: 0864: 00000000 >> > nouveau 0000:02:00.0: disp: 0868: 00000000 -> 04000500 >> > -nouveau 0000:02:00.0: disp: 086c: 00000000 -> 00100500 >> > -nouveau 0000:02:00.0: disp: 0870: 0000e900 -> 00001e00 >> > +nouveau 0000:02:00.0: disp: 086c: 00000000 -> 00100a00 >> > +nouveau 0000:02:00.0: disp: 0870: 0000e900 -> 0000e800 >> > nouveau 0000:02:00.0: disp: 0874: 00000000 -> ffff0000 >> > nouveau 0000:02:00.0: disp: 0878: 00000000 >> > nouveau 0000:02:00.0: disp: 0880: 05000000 >> > >> > Looks like it's using 8bpp (0x1e00) in 32MB case but 16bpp (0xe800) in >> > 64MB case. Why? >> > >> > I get blank screen even with 64MB with video=1280x1024-8 kernel >> > parameter. Console works with video=1280x1024-16 even with 32MB stolen >> > memory. >> > >> > Conclusions: 8-bit support is broken and bpp reduction is weird. >> >> OK, well that makes a *ton* of sense (8bpp being broken). >> >> I think the idea of bpp reduction is that when you're on your shiny >> new Riva TNT with 16MB of VRAM, you don't want to go crazy allocating >> all that to a pinned fbcon - almost half of that would go to a single >> 32bpp 1600x1200 buffer, more for 1920x1200. You want to be able to >> have at least a few fb-sized buffers for backbuffer rendering, etc. >> >> The specific limits could probably use tweaking - I think they only >> consider VRAM size, not the fb size. >> >> I guess 8bpp worked prior to the change you bisected though, so we >> should figure out what we did wrong in the new code. > > Yes, booted 3.7 (last working kernel) and it's running in 8bpp.
By the way, instead of booting $kernel, you can use modetest from libdrm/tests. Not sure if it supports C8 though =/
I think the issue is this:
- OUT_RING(evo, nv_crtc->lut.depth == 8 ? - NV50_EVO_CRTC_CLUT_MODE_OFF : - NV50_EVO_CRTC_CLUT_MODE_ON);
Whereas now we always set 0xC0000000 (aka "ON").
-ilia
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