denial
04-25-06, 08:06 PM
I have the tv-out of my geforce2 mx configured as second X screen at 720x576.
The TV encoder on that card is a Chrontel CH7007. The driver is 1.0-7174.
As I watched the output with a Brooktree 878 TV card, I noticed a black border on both sides. To check this, I sampled luma (SVIDEO connection) of a field at 35MHz (using bttv's VIDEO_PALETTE_RAW (http://www.linuxtv.org/v4lwiki/index.php/VIDEO_PALETTE_RAW)).
The sampled field shows that the PAL active line correctly starts at 10.5µs, but screen contents starts 1.83µs later. The 720 pixel have a length of 48.8µs and are followed by 1.56µs at black level.
64µs/PAL line*720px/48.8µs=944px/PAL line
The Chrontel CH7007 Datasheet (http://www.chrontel.com/pdf/7007.pdf) lists only one PAL mode with a horizontal total of about 944 pixels and without vertical scaling (mode 19 in table 13 on page 24). I suspect that this 800x600 mode is set , but only 720 pixels/line (as configured) are sent to the CH7007. If there was an easy way to access the I2C bus, I'd verify that.
The NVIDIA driver should not use that mode 19 for 720x576. Mode 19 should be used to offer a square pixel 768x576 resolution. The left black border should be compensated for by either moving the hsync closer to the beginning of the next line or by programming the SAV register in the CH7007.
The hsync is not configurable by the user. In fact modelines are completely ignored (on CH7007 tv-out) after their existence has been checked.
The TV encoder on that card is a Chrontel CH7007. The driver is 1.0-7174.
As I watched the output with a Brooktree 878 TV card, I noticed a black border on both sides. To check this, I sampled luma (SVIDEO connection) of a field at 35MHz (using bttv's VIDEO_PALETTE_RAW (http://www.linuxtv.org/v4lwiki/index.php/VIDEO_PALETTE_RAW)).
The sampled field shows that the PAL active line correctly starts at 10.5µs, but screen contents starts 1.83µs later. The 720 pixel have a length of 48.8µs and are followed by 1.56µs at black level.
64µs/PAL line*720px/48.8µs=944px/PAL line
The Chrontel CH7007 Datasheet (http://www.chrontel.com/pdf/7007.pdf) lists only one PAL mode with a horizontal total of about 944 pixels and without vertical scaling (mode 19 in table 13 on page 24). I suspect that this 800x600 mode is set , but only 720 pixels/line (as configured) are sent to the CH7007. If there was an easy way to access the I2C bus, I'd verify that.
The NVIDIA driver should not use that mode 19 for 720x576. Mode 19 should be used to offer a square pixel 768x576 resolution. The left black border should be compensated for by either moving the hsync closer to the beginning of the next line or by programming the SAV register in the CH7007.
The hsync is not configurable by the user. In fact modelines are completely ignored (on CH7007 tv-out) after their existence has been checked.