<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <meta name="Generator" content="Microsoft Exchange Server">  <style></style> </head> <body> <font face="Calibri" size="2"><span style="font-size:10.5pt;"> <div align="left" style="text-align:justify;">Hi, All</div> <div align="left" style="text-align:justify;"> </div> <div align="left" style="text-align:justify;">One question puzzle me is the update point of some register like DSPASURF (<font face="Arial" size="2"><span style="font-size:9pt;">7019Ch</span></font><font face="Arial" size="2"><span style="font-size:9pt;">), in Bspec it men</span></font><font face="Arial" size="2"><span style="font-size:9pt;">tioned that it is at </span></font><font face="Arial" size="2"><span style="font-size:9pt;">“</span></font><font face="Arial" size="2"><span style="font-size:9pt;">Start of </span></font><font face="Arial" size="2"><span style="font-size:9pt;">vertical</span></font><font face="Arial" size="2"><span style="font-size:9pt;"> blank or pipe disbaled</span></font><font face="Arial" size="2"><span style="font-size:9pt;">”</span></font><font face="Arial" size="2"><span style="font-size:9pt;">. </span></font></div> <div align="left" style="text-align:justify;"><font face="Arial" size="2"><span style="font-size:9pt;">So it means that if pipe disabled, the writing of DSPASURF have effect on hardware status once this writing complete and we do not need to wait some extra 20ms </span></font></div> <div align="left" style="text-align:justify;"><font face="Arial" size="2"><span style="font-size:9pt;">Or some vblank interval. But I observed during display mode setting of i915, when pipe disabled, it still use intel_wait_for_vblank() (used in ironlake_crtc_mode_set() )</span></font></div> <div align="left" style="text-align:justify;"><font face="Arial" size="2"><span style="font-size:9pt;">to delay 50ms. So this should be unnecessary right ? </span></font></div> <div align="left" style="text-align:justify;"><font face="Times New Roman"> </font></div> <div align="left" style="text-align:justify;"><font face="Arial" size="2"><span style="font-size:9pt;">Thanks</span></font></div> <div align="left" style="text-align:justify;"><font face="Arial" size="2"><span style="font-size:9pt;">Anhua</span></font></div> <div align="left" style="text-align:justify;"><font face="Times New Roman"> </font></div> </span></font> </body> </html>