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<p class=MsoPlainText><font size=3 color=navy face="Times New Roman"><span
lang=EN-US style='font-size:12.0pt;font-family:"Times New Roman";color:navy'>Hi,
Frantisek:<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=3 color=navy face="Times New Roman"><span
lang=EN-US style='font-size:12.0pt;font-family:"Times New Roman";color:navy'> Thank
you for your reply!<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=3 color=navy face="Times New Roman"><span
lang=EN-US style='font-size:12.0pt;font-family:"Times New Roman";color:navy'> But
I am still wondering why the screen will not flicker if the DMA only refreshes when
the data changed. Does Nokia uses something like smart panel?<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=3 color=navy face="Times New Roman"><span
lang=EN-US style='font-size:12.0pt;font-family:"Times New Roman";color:navy'><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=3 color=navy face="Times New Roman"><span
lang=EN-US style='font-size:12.0pt;font-family:"Times New Roman";color:navy'>Best
Regards<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=3 color=navy face="Times New Roman"><span
lang=EN-US style='font-size:12.0pt;font-family:"Times New Roman";color:navy'>Huang
Gao(</span></font><font size=3 color=navy><span style='font-size:12.0pt;
color:navy'>黄杲</span></font><font size=3 color=navy face="Times New Roman"><span
lang=EN-US style='font-size:12.0pt;font-family:"Times New Roman";color:navy'>)<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>-----</span>邮件原件<span lang=EN-US>-----<br>
</span>发件人<span lang=EN-US>: Frantisek Dufka [mailto:dufkaf@seznam.cz] <br>
</span>发送时间<span lang=EN-US>: <st1:chsdate IsROCDate="False" IsLunarDate="False"
Day="13" Month="1" Year="2009" w:st="on">2009<span lang=EN-US><span lang=EN-US>年1</span></span><span
lang=EN-US><span lang=EN-US>月13</span></span><span lang=EN-US><span
lang=EN-US>日</span></span></st1:chsdate> 16:56<br>
</span>收件人<span lang=EN-US>: Huang Gao (Gmail)<br>
</span>抄送<span lang=EN-US>: maemo-developers@maemo.org<br>
</span>主题<span lang=EN-US>: Re: Does anyone know the mechanism in Nokia's LCD
driver?</span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>Huang Gao (Gmail) wrote:<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>> Dear all Maemo fans:<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>> <o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>> I just noticed that Maemo
used a different mechanism in LCD <o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>> driver from normal FB drivers. It seemed that Maemo does not use
the <o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>> automatic DMA refresh in the driver, which is replaced by an ioctl
named <o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>> OMAPFB_UPDATE_WINDOW, and a method called TEARSYNC. However, I am <o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>> confused why it will improve the performance of graphics
applications. <o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>> Is there anyone that may give me some tips on this topic?<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>This was done because of relatively high resolution (800x480x16 bits).<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>Automatic DMA would continuously steal a lot of SDRAM cycles and slowed<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>down everything. Perhaps it would also eat more power and prevented<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>system from sleep when the display is on.<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>I wonder if this is still the case for upcoming OMAP3 based device.<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>BTW, there is kernel ioctl to set automatic refresh and the refresh rate<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>can be tweaked in kernel source but the results are suboptimal. Maybe at<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>least for Nokia 770 it would be possible to use tearsync flag for such<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>automatic update and set the update timer to lcd refresh rate or lcd<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>refresh rate/2 to get nice result. N8x0 cannot update whole screen in<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>one lcd refresh cycle anyway so you'll always get tearing on the bottom.<o:p></o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US><o:p> </o:p></span></font></p>
<p class=MsoPlainText><font size=1 face=宋体><span lang=EN-US style='font-size:
9.0pt'>Frantisek<o:p></o:p></span></font></p>
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