Gentoo Archives: gentoo-user

From: Kevin O'Gorman <kogorman@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] New HD monitor stretches everything. How to teach Xorg?
Date: Wed, 25 Aug 2010 20:30:28
Message-Id: AANLkTi=Qys7JMwT=tUsT86zFY76g1QfowtiEn7zoe8qt@mail.gmail.com
In Reply to: Re: [gentoo-user] New HD monitor stretches everything. How to teach Xorg? by Paul Hartman
1 On Wed, Aug 25, 2010 at 7:57 AM, Paul Hartman
2 <paul.hartman+gentoo@×××××.com<paul.hartman%2Bgentoo@×××××.com>
3 > wrote:
4
5 > On Wed, Aug 25, 2010 at 9:44 AM, Mick <michaelkintzios@×××××.com> wrote:
6 > > On 25 August 2010 15:38, Paul Hartman <paul.hartman+gentoo@×××××.com<paul.hartman%2Bgentoo@×××××.com>>
7 > wrote:
8 > >> On Wed, Aug 25, 2010 at 9:25 AM, Mick <michaelkintzios@×××××.com>
9 > wrote:
10 > >>> On 25 August 2010 15:17, Paul Hartman <paul.hartman+gentoo@×××××.com<paul.hartman%2Bgentoo@×××××.com>>
11 > wrote:
12 > >>>> On Tue, Aug 24, 2010 at 7:03 PM, Kevin O'Gorman <kogorman@×××××.com>
13 > wrote:
14 > >>>>> I found the specs with Hsync and VSync limits, but they don't mention
15 > the
16 > >>>>> clock speed. I guess I'll just have to fool with it until it works
17 > or
18 > >>>>> catches fire.
19 > >>>>
20 > >>>> That basically describes the way I've done my X monitor settings for
21 > >>>> the past 10 years or so. I just made up a bunch of numbers and hope
22 > >>>> they accidentally work. :) Now I'm thankful for EDID in monitors and
23 > >>>> smarter video drivers.
24 > >>>
25 > >>> I think that if xrandr -q does not show the resolution you are
26 > >>> seeking, then the video card or driver in question cannot provide it.
27 > >>> I'm not sure that feeding xorg any odd modeline will change things,
28 > >>> plus unlike a CRT monitor, LCDs only provide a clear image at their
29 > >>> native resolution (denoted by '+' in the xrandr list of resolutions)
30 > >>
31 > >> I've been able to generate modelines in the past for all kinds of
32 > >> crazy non-standard resolutions. I think the ones listed may be the
33 > >> ones defined in the card's BIOS.
34 > >>
35 > >> I just remembered about CVT, I think it's what I used to generate the
36 > >> modelines I posted earlier. It is part of the x11-base/xorg-server
37 > >> package and will generate the frequencies and everything for you based
38 > >> on VESA standards. You simply give it X and Y resolution and it does
39 > >> the rest. For example:
40 > >>
41 > >> $ cvt 1280 720
42 > >> # 1280x720 59.86 Hz (CVT 0.92M9) hsync: 44.77 kHz; pclk: 74.50 MHz
43 > >> Modeline "1280x720_60.00" 74.50 1280 1344 1472 1664 720 723 728
44 > >> 748 -hsync +vsync
45 > >
46 > > Fair enough, but anything other than the native resolution on an LCD
47 > > monitor will end looking distorted or blurred.
48 >
49 > Of course, and I agree completely, but what I was going for was at
50 > least he can get blurry 16:9 that fills the whole screen rather than
51 > 4:3 that is either stretched or leaves gaps on the sides. :)
52 >
53 >
54 Precisely my goal when I started this thread. In my case, native appears to
55 be 1920x1080.
56 With no xorg.conf, X finds 1280x1024, which is usable either stretched, or
57 with the gaps.
58 There is no discernable flicker, blur or distortion, just capacity that is
59 not being used.
60
61 There are some confusing things about this.
62 - The log contains 1920x1080 modelines, but is not using them or clearly
63 stating the reason.
64 - The log contains the lines
65 (!!) MACH64(0): Virtual resolutions will be limited to 8191 kB
66 due to linear aperture size and/or placement of hardware cursor
67 image area.
68
69 I have no idea how to reconcile that with the fact that the resolution
70 being used results in
71 1310720 (1.3 million) pixels, at 3 bytes (24 bits) per pixel, which
72 sounds to me like over
73 3 megabytes. The desired resolution would have 2073600 (2 million)
74 pixels and about
75 6 megabytes. They sound too big, but the first one actually works. I
76 don't understand this at all.
77
78 - (--) MACH64(0): Internal programmable clock generator detected.
79 (--) MACH64(0): Reference clock 157.5/11 (14.318) MHz.
80 (II) MACH64(0): <default monitor>: Using hsync range of 30.00-85.00 kHz
81 (II) MACH64(0): <default monitor>: Using vrefresh range of 55.00-75.00 Hz
82 (II) MACH64(0): <default monitor>: Using maximum pixel clock of 160.00
83 MHz
84 (II) MACH64(0): Estimated virtual size for aspect ratio 1.7931 is
85 1920x1080
86 (this bothers me because, 1920/1080 is
87 more like 1.7777)
88 (II) MACH64(0): Maximum clock: 120.00 MHz
89
90 So it's still contemplating 1920x1080, but mentions both 120MHz and 160MHz
91 as the max
92 for pixel clock. Anyway, for 2 million pixels, 120MHz is not going to cover
93 any overhead at 60 Hz, and 55Hz might not make it either. Maybe the MACH64
94 cannot actually get above 120 MHz. How to find out if that's what the log
95 is trying to say?
96
97 - it complains about memory for 2048x1536, but not for anything smaller (I
98 don't think the monitor has that many pixels anyway.) So I guess there's
99 memory enough for all the others. Instead it complains about many modelines
100 in this fashion (but showing just the last 2 lines)
101 (II) MACH64(0): Not using driver mode "1920x1080" (bad mode
102 clock/interlace/doublescan)
103 (WW) MACH64(0): Shrinking virtual size estimate from 1920x1080 to
104 1280x1024
105
106
107 --
108 Kevin O'Gorman, PhD

Replies

Subject Author
Re: [gentoo-user] New HD monitor stretches everything. How to teach Xorg? Walter Dnes <waltdnes@××××××××.org>