Hi Geert
On Fri, 4 Jun 2010, Geert Uytterhoeven wrote:
> On Fri, Jun 4, 2010 at 17:27, Guennadi Liakhovetski
> <g.liakhovetski@xxxxxx> wrote:
> > I'm trying to configure an HDMI controller on an ARM based SoC, and I
> > cannot seem to find suitable values for blanking parameters.
> >
> > The monitor EDID reports 1280x1024@108MHz:
> >
> > H_ACTIVE = 1280
> > H_SYNC_OFFSET = 48
> > H_SYNC_WIDTH = 112
> > H_BLANKING = 408
> >
> > V_ACTIVE = 1024
> > V_SYNC_OFFSET = 1
> > V_SYNC_WIDTH = 3
> > V_BLANKING = 42
> >
> > The HDMI controller can be programmed in one of two modes: with a preset
> > configuration or manually specifying each parameter. The only mode that
> > somehow works up to now is the preset 1280x720@xxxxxxxxx With this mode
> > the image on the monitor is stretched vertically, but it works.
> > Unfortunately, the controller doesn't have any preset modes for 1280x1024
> > or for anything close enough. So, I have to support manual geometry
> > configuration. To reduce the number of required changes, as a first step,
> > I'm trying to achieve the same result in manual mode, as I've got with
> > preset, by programming 1280x720. For this I've chosen the following
> > configuration:
> >
> > .xres = 1280,
> > .yres = 720,
> > .left_margin = 224,
> > .right_margin = 104,
> > .hsync_len = 40,
> > .upper_margin = 20,
> > .lower_margin = 5,
> > .vsync_len = 5,
> >
> > which is the same, as what I'm configuring my LCD controller
> > with. This translates to
> >
> > H_ACTIVE = 1280
> > H_SYNC_OFFSET = 104
> > H_SYNC_WIDTH = 40
> > H_BLANKING = 368
> >
> > V_ACTIVE = 720
> > V_SYNC_OFFSET = 5
> > V_SYNC_WIDTH = 5
> > V_BLANKING = 30
> >
> > With it the monitor recognises the signal, the LED goes green, but there's
> > no image.
> >
> > I've done a few more tests with various configurations, but so far with no
> > success. Can anyone suggest how to debug this? How to find the proper
> > video mode?
>
> The timings I calculated from the HDTV specs for ps3fb are slightly different.
> But you may want to give them a try.
You're referring to this mode from drivers/video/ps3fb.c:
}, {
/* SXGA */
"sxga", 60, 1280, 1024, 9259, 248, 48, 38, 1, 112, 3,
FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT, FB_VMODE_NONINTERLACED,
FB_MODE_IS_VESA
}, {
right? Interestingly, those are exactly the values, that my monitor is
reporting, also quoted at the top of this mail:
248 + 48 + 112 = 408
38 + 1 + 3 = 42
, and I cannot seem to get them to work:( hmm...
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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