Hi Kevin, On 18/03/2017 22:32, Kevin Brace wrote: > Hi Xavier, > > Sorry for missing the reply for several days, but I have been > thinking about this issue for the past few days.
No worries. > I have several possible explanations as to why things are not > working. Of course, it is not proven so you will need to test it > yourself. Xavier, since you mentioned pitch, I noticed that when > reading the Xorg.0.log, I noticed that the screen resolution is 1368 > x 768. I believe the correct resolution is 1366 x 768. I know that > sounds strange, but VIA EPIA-M830 user manual lists the panel index, > and it assigns 1366 x 768 for panel index 10. Yes, 1366 is a number > that is not dividable by 8, but for some reason, the flat panel > industry uses this odd resolution for some FPs. That doesn't surprise me that much, iirc the (now mostly defunct) Samsung NC20 I own used 1366x768 too. I'd really need to fix it someday... > You might be wondering why this causes the old code which allowed > IGA1 to work fine with 1366 x 768 flat panel, but not with IGA2. Due > to the way IBM developed VGA (and probably this goes back to EGA and > even Motorola MC6845 I suppose), when IGA1 horizontal display period > is set, the value being set has to be shifted by 3 bit positions (8 > pixel boundary). IGA1 pretty much drags the original VGA way of > setting the horizontal display period since it is a superset of VGA, > but IGA2 is implemented without such restriction since it is a clean > sheet design. IGA2 horizontal resolution can be set at 1 pixel > boundary. Since you were using 1368 instead of 1366, this means that > all other display parameters get messed up like blank period and sync > period as well. Just gave it a try with 1366x768 instead of 1368x768, but that doesn't help. The screen is still distorted, not the same, but similarly. Also, the part of the screen displaying a picture is now bigger, it's covering half the height of the screen, rather than one third with 1368x768. > I know that the screen can easily get messed up if these numbers are > off even slightly, so this might be why you are seeing a distorted > picture with V2 and V3 patches I sent to you. That being said, you > said you are seeing a cursor with the V2 and V3 patches that > previously did not display. The only condition I was not sure there was a cursor is when using 0.6.0 + panel id fix (1368x768) + via_regs_dump -w 3d5.99 0x11 I just checked and the cursor is there too. Both v2 and v3 also have the cursor. Oh, and not sure I mentioned it, the cursor looks fine. it's not distorted in any way. > This probably means that not specifying IGA2 for LVDS1 was one of the > reason why the screen regression happened, but also 1366 vs. 1368 > issue came into play, and I also speculate IGA2 itself is far more > sensitive to the display period being off by even 2 pixels. > Let's assume the Epia M830 manual is correct. I can't get my hands on the manual for this laptop to make sure of the expected resolution (assuming the manual specify it and is correct indeed) at the moment, I will need to dig deeper, I'm not even sure there was one in the first place. Can't find it on the net either, this is a noname computer, likely a reference design for VIA, who sent it to me for testing purposes back in the days. dmidecode says : Manufacturer: iDOT Computers, Inc. Product Name: L740 Any other idea ? Regards, Xavier > Regards, > > Kevin Brace The OpenChrome Project maintainer / developer > > >> Sent: Thursday, March 16, 2017 at 11:17 AM From: "Xavier Bachelot" >> <xav...@bachelot.org> To: "Kevin Brace" <kevinbr...@gmx.com> Cc: >> openchrome-devel@lists.freedesktop.org Subject: Re: >> [Openchrome-devel] openchrome 0.6.0 regressions on VX900 laptop >> >> Hi Kevin, >> >> On 15/03/2017 23:33, Kevin Brace wrote: >>> Try this third version of the patch. I changed the FP power on / >>> off code to use software controlled method already proven with >>> CX700 / VX700 and VX800 chipsets. >>> >> No improvement over patch v2 with patch v3. I haven't collected >> neither log nor regs dump though. >> >> I started to poke at register manually after applying v2 the other >> day, but no luck. Is there any specific range of registers that are >> more likely than others to help ? >> >> Would a picture of the distorted screen, together with a picture of >> how it should look like, help ? I don't know how to describe the >> distortion, a picture is worth a thousand word :-) The display is >> compressed in the top third or half of the screen, and diagonally >> stretched to the right. The remaining bottom part of the screen >> seems like uninitialized memory. It seems like the framebuffer is >> using a different horizontal resolution than the display. Could it >> be something like wrong "pitch" ? >> >> Regards, Xavier >> _______________________________________________ Openchrome-devel mailing list Openchrome-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/openchrome-devel