Xorg/xfce4 vs. NVIDIA GeForce4 Ti 4600 on PowerMac G4: an odd display problem

[Mark Millard]

Context: I've updated to ports r368074 which updated Xorg, the drivers, and even gcc (to 4.8.3). I used portmaster -t -D -a. This was on...

FreeBSD FBSDG4S0 10.1-PRERELEASE FreeBSD 10.1-PRERELEASE #0 r271215: Sat Sep  6 23:56:15 PDT 2014     root at FBSDG4S0:/usr/obj/usr/src/sys/GENERIC  powerpc

which was then used on a...

NVIDIA GeForce4 Ti 4600 when used at 1680x1050 on a PowerMac G4 Dual (1.4GHz FW800)

The update did not change the display oddity. But I need to correct part of my description and possibly improve its form. There is a band of missing pixels.

Imagine the display in 5 vertical bands: A,B,C,D,E (left to right).

A: 8 pixels wide or so.
B: 8 pixels wide or so.
D: 8 pixels wide or so.
E: 8 pixels wide or so.

C: The rest of the width in the middle.

So a correct display would have (in order) A, B, C, D, E.

What I actually get is (in visual left to right order): A, E, A, B, C.

For example if part of the cursor is in A then one sees it twice. One does not see anything from D. The cursor can be visibly moved from C to E and back without the cursor traveling in the middle.

E also appears to be shifted down a pixel from what it should be.

This is not a change from the actual behavior before: I just had the description wrong before.

(xorg.conf is as Xorg -configure generated it. The updated Xorg generates the same as before.)



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Mark Millard
markmi at dsl-only.net

On Sep 8, 2014, at 4:43 AM, Mark Millard <markmi at dsl-only.net> wrote:

[This message gives what was a side note in another message its own message.]

NVIDIA GeForce4 Ti 4600 when used at 1680x1050 (at least on an ADC display from a G4 PowerMac):

What should be the last 8 pixels or so on the right are instead near the left hand side of the display, about 8 pixels from the left side in fact. (This had been observed before the fix after a ports update but with the hang/quit status I did not want to assume much about the incomplete display updates at the time.)

In total all the pixels are probably there. There is just a band of pixels that is way out of place. (So all the pixels after them are then shifted from where they should be by the width of that band.)

Also the oddly placed, about 8 pixel wide band appears to be shifted down one pixel from what would be expected. (Easily visible at the edge of the menu bar across the top.)

At 1400x1050 there are no such problem bands. Nor probably at 1280x1024. (But 1280x1024 is not a nice display in many other ways. I did not look carefully at 1280x1024.)

The Xorg.0.log's do show an alternate Modeline for 1680x1050:

[    73.585] (**) NV(0): *Driver mode "1680x1050": 117.1 MHz, 63.7 kHz, 59.9 Hz
[    73.585] (II) NV(0): Modeline "1680x1050"x59.9  117.13  1680 1744 1776 1840  1050 1053 1056 1062 +hsync +vsync (63.7 kHz ezP)
[    73.585] (**) NV(0): *Driver mode "1680x1050": 119.0 MHz, 64.7 kHz, 59.9 Hz
[    73.585] (II) NV(0): Modeline "1680x1050"x59.9  119.00  1680 1728 1760 1840  1050 1053 1059 1080 +hsync -vsync (64.7 kHz ez)
[    73.585] (**) NV(0): *Default mode "1400x1050": 122.0 MHz, 64.9 kHz, 60.0 Hz
[    73.585] (II) NV(0): Modeline "1400x1050"x60.0  122.00  1400 1488 1640 1880  1050 1052 1064 1082 +hsync +vsync (64.9 kHz zd)
[    73.585] (**) NV(0): *Default mode "1280x1024": 108.0 MHz, 64.0 kHz, 60.0 Hz
[    73.585] (II) NV(0): Modeline "1280x1024"x60.0  108.00  1280 1328 1440 1688  1024 1025 1028 1066 +hsync +vsync (64.0 kHz zd)


The other NVIDIA cards and the Radeon's that I tried in various G4 and G5 PowerMac's do not show this display problem at the pixel counts that they allow. The display works normally under Mac OS X 10.4 and 10.5.


Context:

FreeBSD FBSDG4S0 10.1-PRERELEASE FreeBSD 10.1-PRERELEASE #0 r271215: Sat Sep  6 23:56:15 PDT 2014     root at FBSDG4S0:/usr/obj/usr/src/sys/GENERIC  powerpc

portsnap was used and all ports were rebuilt from scratch, including Xorg and xfce4.




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Mark Millard
markmi at dsl-only.net