From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timur Tabi Date: Mon, 19 Dec 2011 16:08:38 +0000 Subject: Re: Should I use FBINFO_VIRTFB? Message-Id: <4EEF6186.1030901@freescale.com> List-Id: References: <4EEA5DA7.3010406@freescale.com> In-Reply-To: <4EEA5DA7.3010406@freescale.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-fbdev@vger.kernel.org Geert Uytterhoeven wrote: >> > I'm a little confused about panning support in my driver (which I didn't write -- I'm just cleaning it up). There is .fb_pan_display function, but it only gets called early in the boot process, and only with xoffset=0 and yoffset=0. After that, it never seems to get called again. Under what circumstances is panning really used? > Is yres_virtual larger than yres? Is the font size a multiple of ypanstep? > If not, panning is disabled. I can't seem to get partial panning to "activate", no matter what I do. I set 'flags' to FBINFO_DEFAULT | FBINFO_VIRTFB | FBINFO_PARTIAL_PAN_OK | FBINFO_READS_FAST. I have a 1280x1024 monitor. I set the virtual_size to 1280,1280 via sysfs. Then I set panning to "0,100", and I see the screen scroll. I tried sending a bunch of output to /dev/tty1, but no matter what I do, none of the SCROLL_PAN_REDRAW or SCROLL_PAN_MOVE case statements in fbcon_scroll() get executed. At this point, should I just FBINFO_VIRTFB | FBINFO_PARTIAL_PAN_OK | FBINFO_READS_FAST and not worry about whether it really makes a difference? -- Timur Tabi Linux kernel developer at Freescale