From mboxrd@z Thu Jan 1 00:00:00 1970 From: fuhz@free.fr Date: Tue, 09 Mar 2010 09:50:32 +0000 Subject: How to know that a refresh is required ? Message-Id: <1268128232.4b9619e871ed7@imp.free.fr> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-fbdev@vger.kernel.org Hi ! I am currently writing a FrameBuffer driver for a custom embedded board. I already read some documentation, including skeletonfb.c and vfb.c. There are still some details that I don't really understand. My board has a LCD controller which has its own internal buffer. I am using DMA transfer to modify this buffer when I need to update the screen. Programs using the framebuffer drivers (ie. gui apis) can write anytime to the framebuffer internal buffer trough nmap. My question : how do I know when to refresh my screen ? Currently, I am thinking about these solutions : - endless DMA transfer : the screen is always refresh (consumes power) - timer based solution : refresh the screen every n milliseconds (latency) I am waiting for your advices ! Are there other solutions ? Thanks for all. Best regards. fuhz PS: I need to run GTK on an embedded board. So I guess writing a FrameBuffer driver is not a bad choice.