On Wed, Nov 26, 2008 at 1:04 AM, Mathieu Comandon <[EMAIL PROTECTED]>wrote:
> Jordan Crouse a écrit : > > Bert Freudenberg wrote: >> >>> >>> On 25.11.2008, at 17:37, Jordan Crouse wrote: >>> >>> Bert Freudenberg wrote: >>>> >>>>> On 25.11.2008, at 11:57, Strider wrote: >>>>> >>>>>> Hi, >>>>>> I have a XO Laptop which is a nice machine machine with a high res >>>>>> display of 1200x900 pixels. The problem with this is that the laptop >>>>>> isn't >>>>>> powerful enugh to handle fullscreen applications at this resolution. If >>>>>> only the display could switch to a lower resolution things would be much >>>>>> better but it seems that this laptop only supports a single resolution. >>>>>> >>>>>> So I was wondering if it would be possible of simulating lower res at >>>>>> a low level, that is the xf86-video-geode driver. >>>>>> I'm not an expert in video drivers but i imagine that there are >>>>>> functions to request a pixel to be drawn on screen based on what's in >>>>>> the >>>>>> video ram. >>>>>> Now let's say that it's not one pixel but two that we put on screen, >>>>>> and that we draw each lines two times. That would result in a 600x450 >>>>>> resolution. >>>>>> If we do the same thing but repating the operations three times , we >>>>>> would have a 400x300 resolution. >>>>>> Some emulators have a scale option to do such a thing and manage it >>>>>> quite well, but if we had such an option in the video driver, the >>>>>> result >>>>>> would be even faster ! >>>>>> >>>>>> So what do you think about this? Is it possible ? >>>>>> >>>>> The Geode actually can do real upscaling (that is, scale multiple >>>>> graphics resolutions to the panel resolution), it works fine on other >>>>> machines and LCDs. But latest word is that this somehow interacts badly >>>>> with our DCON, so no-one has gotten it to work correctly on the XO yet. >>>>> >>>> >>>> Indeed. I think there is a DCON interaction happening, because the >>>> mouse gets "corrupted" during upscaling as well - and that implies that the >>>> issue is happening after the screen is constructed. The upscaling works >>>> fine on a CRT and on a "standard" TFT panel, so that is what leads me back >>>> to the DCON. Its also a long shot that the 1200x900 resolution is >>>> confusing >>>> the scaler, but I doubt it since the aspect ratio is still 4:3. I would >>>> love for other people to try the driver (it is in the latest debxo, I >>>> think); perhaps you can see the pattern that I can't. >>>> >>>> There still may be hope, because the video upscaler can take RGB 5:6:5 >>>>> data, so in theory a lower-res 16 bpp frame buffer could be upscaled >>>>> on-the-fly (and the upscaler does 30 fps easily). But I guess getting >>>>> this >>>>> to work would require a very determined X hacker ... >>>>> >>>> >>>> The RGB video overlay should just work (TM). So it would take less of a >>>> determined X hacker, and more of a determined application hacker to put all >>>> the pieces together. >>>> >>> >>> >>> Well, I meant that this could be used to actually provide, say, an >>> 800x600x16 mode in the driver, without having to hack applications. While >>> adapting a single app may be comparatively easy, it's still a major hassle >>> to patch each and every app. Having it in the driver would make things just >>> work (TM). But that would be a major hack, don't you agree? >>> >> >> So if I understand what you are getting at - you want to set up a single >> overlay over the whole screen, and render everything on that? Thats >> probably doable - you could set up a shadow framebuffer like we do for >> rotation, and hook the damage code into the video overlay. It might work >> out well, but it would preclude using the video overlay for anything else >> (such as, video). It would probably also preclude rotation - maybe not. >> >> But rather then invent fanciful ways to handle this, the efforts would be >> better spent figuring out how to fix the current driver. Mitch reports that >> the Windows driver works just fine, so clearly the bug is on our side. >> >> We need developers to start understanding how the driver works. Everybody >> with a professional interest in the X driver has moved on to other pastures, >> and OLPC desperately needs community members to pick up the slack. >> >> Jordan >> >> Knowing that changing resolution on Windows XP sure brings hope to solve > this problem :) > I have installed the latest DebXO on a SD Card and xrandr shows several > choices where Ubuntu and Fedora showed only the native 1200x900. > I tried the other modes but they're all messed up. It's clearly a problem > about timings. > Here's a photo of what it looks like when I try run run Scummvm in > fullscreen mode : http://img155.imageshack.us/img155/5589/img0700qg4.jpg > > I had a similar "out of sync" problem on my other laptop back when the > radeon driver had problems on my display. Windows XP had no problems and I > had a tool which allowed me to find the correct timing to add valid > ModeLines to xorg.conf. Later versions of Ubuntu corrected this problem and > I could switch resolutions without any problems. I hope the same thing will > happen with the Geode driver soon :) > The tool is was talking about in my last message is powerstrip , I has an advanced timings options window (Screenshot here : http://img383.imageshack.us/img383/3429/powerstriprw1.jpg ) which can be used to get values for the xorg.conf. Hope this can help.
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