From: Matthew L. <Mat...@mo...> - 2004-10-25 13:25:24
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On Sat, Oct 23, 2004, Brian Dushaw wrote: {snip} > Naively, it seems to me that this size of resolution is a bit much for the > netbook's 640x480 screen, but I can't say that I understand anything at all > about driving the touchscreen... In this case the driver is just using the values it gets from the hardware. To me it seems most logical to use these hardware values when calibrating. However, for reading points, the Summa protocol includes commands to set the resolution to certain fixed values. Currently the driver ignores these requests and just continues to use the hardware values. There are stubs for these requests in the driver (currently #if 0'ed out and more for documentation purposes, since I hadn't anticipated them being of any real use). By default XFree86 requests 500dpi, but the driver continues to use a grid of around 3200x3495 points. Assuming a screen diagonal of 7.7inches, this corresponds to a touchscreen resolution of approx 520dpi in the x direction and 750dpi in the y direction (assuming I didn't just mess up my calculations). So the values from the hardware aren't exactly what X expects, but they're of a similar order of magnitude. The main problem is if anything used those dimensions to calculate the screen dimensions - it would deduce that the netBook screen is taller than it is wide. You can change what resolution X requests by adding eg the following line to the Touchscreen InputDevice section of your XF86Config-4: Option "Resolution" "200" As far as I know the following are possible valid Resolution values that can be set by the Summa protocol: (in dpi) 100, 200, 254(=10 lpmm), 400, 500, 508(=20 lpmm), 1000, 1016(=40 lpmm), 2000. If you try to use other values in XF86Config-4 they just get ignored by XFree86, and it uses the default value of 500dpi instead. But as I say, the driver currently ignores any request to change the resolution anyway, so this has no real effect. > I also note that 4 buttons are now defined, so that the .keylaunchrc > file I use needs, e.g., "pointer 1 2 3 4", etc. for xmodmap to work > properly. That's slightly surprising to me - I'd expect three buttons. I'm guessing wildly, but possibly one of them corresponds to "no button", or possibly to left-and-right buttons simultaneously, as used by X's emulate three buttons feature. (I'm not actually using the S7 for anything practical yet, so I haven't got any right-click mechanism setup). -Matthew. |