<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">fyi<br><div><br><div>Begin forwarded message:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>From: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Carsten Haitzler (The Rasterman) <<a href="mailto:raster@openmoko.org">raster@openmoko.org</a>></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>Date: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica">March 9, 2008 6:17:56 PM GMT+08:00</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>To: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Andy Green <<a href="mailto:andy@openmoko.com">andy@openmoko.com</a>></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>Cc: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Wolfgang Spraul <<a href="mailto:wolfgang@openmoko.com">wolfgang@openmoko.com</a>>, Sean Moss-Pultz <<a href="mailto:sean@openmoko.com">sean@openmoko.com</a>>, William Lai <<a href="mailto:will@openmoko.com">will@openmoko.com</a>>, "Tony Tu)" <<a href="mailto:tony@openmoko.com">tony@openmoko.com</a>>, matt_hsu <<a href="mailto:matt_hsu@openmoko.org">matt_hsu@openmoko.org</a>>, Chia-I Wu <<a href="mailto:olv@openmoko.com">olv@openmoko.com</a>>, Werner Almesberger <<a href="mailto:werner@openmoko.org">werner@openmoko.org</a>></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>Subject: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica"><b>Re: LCM flicker</b></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div> </div>On Sun, 09 Mar 2008 09:38:30 +0000 Andy Green <<a href="mailto:andy@openmoko.com">andy@openmoko.com</a>> babbled:<br><br><blockquote type="cite">-----BEGIN PGP SIGNED MESSAGE-----<br></blockquote><blockquote type="cite">Hash: SHA1<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Somebody in the thread at some point said:<br></blockquote><blockquote type="cite"><blockquote type="cite">On Sun, 9 Mar 2008 16:15:10 +0800 Wolfgang Spraul <<a href="mailto:wolfgang@openmoko.com">wolfgang@openmoko.com</a>><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">babbled:<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">raster -<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">again, landscape is off right now, we can disable landscape altogether <br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">for now. If you think this can later be fixed in software by using the <br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">2d engine to do in-lace, EVEN BETTER!<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">that's what i said. if u want landscape - u get flicker. too bad. we can<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">disable it in software. i did not advocate that we sink time into fixing it<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">now. we CAN fix it later. we have an opt-out clause.<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">But right now let's focus on the portrait flickering.<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Your observations are great! Real news...<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">well that's just what i noticed. it could also be our 50hz refresh. thats<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">what xrandr says we are doing, and 25hz in landscape mode. that is the<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">killer. the lcm is probably expecting 60hz minimum.<br></blockquote></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Hi Carsten --<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Interesting about the different colour channels acting differently. If<br></blockquote><blockquote type="cite">it is easy for you, maybe you could also try alternate red/blue lines on<br></blockquote><blockquote type="cite">a stride of 2 or 4 for example to see if there is a pathological<br></blockquote><blockquote type="cite">pattern. When we had this bug with the PLL divider register getting<br></blockquote><blockquote type="cite">trashed on the Glamo and we saw really slow refresh (like ~1Hz), I<br></blockquote><blockquote type="cite">noticed there seemed to be some kind of interlace action going on where<br></blockquote><blockquote type="cite">the redraw was happening. It didn't look like true progressive scan.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">If you do the math on the PCLK vs actual overscan effective pixels, it<br></blockquote><blockquote type="cite">comes out to 60Hz is what we deliver in portrait right now. There's no<br></blockquote><blockquote type="cite">way 60Hz noninterlaced refresh should give flicker by itself.<br></blockquote><br>hhmmm. then xrandr is lying to me, it claims 50hz. aqnd it claims 25hz for<br>landscape mode (which explains the much worse flicker).<br><br><blockquote type="cite">Either the refresh action we perform "beats" against another oscialltor<br></blockquote><blockquote type="cite">inside the LCM ("booster" or this "internal" osciallator), or there is<br></blockquote><blockquote type="cite">some kind of PWM trickery used to get the intensity levels that we beat<br></blockquote><blockquote type="cite">against somehow.<br></blockquote><br>i haven't found a pathological pattern yet - but it seems a smooth gradient - in<br>ANY direction seems to bring it out. that doesn't help me figure out what kind<br>of pathological pattern is causing it. for that matter a solid orange color<br>region flickers too - all by itself. no gradient needed.<br><br>rgb: 255 145 0 does a wonder flickering job. this is totally bizarre unles u<br>look at there being some temporal interference pattern on the r & b signals<br>that doesn't affect g, and the interference pattern is inverted between r & b.<br><br><blockquote type="cite">- -Andy<br></blockquote><blockquote type="cite">-----BEGIN PGP SIGNATURE-----<br></blockquote><blockquote type="cite">Version: GnuPG v1.4.7 (GNU/Linux)<br></blockquote><blockquote type="cite">Comment: Using GnuPG with Fedora - <a href="http://enigmail.mozdev.org">http://enigmail.mozdev.org</a><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">iD8DBQFH07AWOjLpvpq7dMoRAiUlAJ9KoQLqsX8hW+IPHwwzU0DfGTRwZgCfRV1Y<br></blockquote><blockquote type="cite">SarAlpZB/cZdMbTe4HfvSzQ=<br></blockquote><blockquote type="cite">=ecwK<br></blockquote><blockquote type="cite">-----END PGP SIGNATURE-----<br></blockquote><br><br>-- <br>Carsten Haitzler (The Rasterman) <<a href="mailto:raster@openmoko.org">raster@openmoko.org</a>><br></blockquote></div><br></body></html>