From mboxrd@z Thu Jan 1 00:00:00 1970 From: siqiaochen@gmail.com (siqiao chen) Date: Wed, 27 Apr 2011 21:47:08 -0700 Subject: Double buffer support in Framebuffer? In-Reply-To: References: Message-ID: To: kernelnewbies@lists.kernelnewbies.org List-Id: kernelnewbies.lists.kernelnewbies.org O, I get it! Thank you for your explanation! On Wed, Apr 27, 2011 at 8:22 PM, Dave Hylands wrote: > Hi Philip, > > Replying to all this time. > > On Wed, Apr 27, 2011 at 4:24 PM, siqiao chen wrote: > > Hello, Could I ask how do I enable double buffer support in FrameBuffer > > device? > > I think I could manually increase xres_virtual/yres_virtual to 2 times of > > the display size in video driver and swap xoffset/yoffset after VSync. > But > > could I know if this is the right way to do double buffering or this > > function is already built-in? > > You're on the right track. You only need to double xres_virtual or > yres_virtual, not both. > > Let's suppose that your display is 800x480. Then your display driver > needs to size the framebuffer to be 800x960, and you'd use > FBIOPAN_DISPLAY to toggle between 0,0 and 0,480. > > The driver has to support the double sized framebuffer and the pan > command (or maybe you can modify yoffset directly? I haven't tried > this approach myself). > > -- > Dave Hylands > Shuswap, BC, Canada > http://www.davehylands.com > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20110427/22356502/attachment.html