On Thu, Feb 18, 2010 at 02:49:34PM -0800, Bernie Thompson wrote: > Hi Greg, > > On Thu, Feb 18, 2010 at 8:01 AM, Greg KH <greg@xxxxxxxxx> wrote: > > This patch adds the warning to the build: > > drivers/staging/udlfb/udlfb.c:65:2: warning: #warning message "FB_SYS_* in kernel or module option to support fb console" > > The intent is you'd get that warning when: > > * You're building udlfb as a module outside of full kernel rebuild > * You don't have a dependency you need (for full functionality) > > If you were doing a full kernel build, Kconfig (as of this patch) > knows the dependencies as should pull them in. > > In this case, your kernel headers say you don't have > CONFIG_FB_SYS_IMAGEBLIT (which is part of the "virtual framebuffer > driver" ops set of BLIT, FILL, etc. which has a lot of (IMHO > incorrectly strong) warnings around it in Kconfig not to enable, since > several drivers are now dependent. > > That dependency is needed for framebuffer consoles (fbcon) to work > properly in udlfb with the current implementation. This post gives a > little background on the different types of framebuffer clients: > http://plugable.com/2010/01/30/linux-kernel-framebuffer-rendering-apis/ > > So you either need to recompile your kernel to get this dependency, or > live without framebuffer console functionality (which many people > don't care about -- but some do a lot). > > Failing compile completely generated a strong response from some users > -- they didn't want to recompile their whole kernel to get a single > module, if the dependency was for functionality they didn't care > about. > > Keeping the #ifdefs but getting rid of the #warnings would mean > silently loosing functionality, which would throw people off later. > > So two questions: > * Is there evidence the #warning is getting triggered in a case where > it shouldn't (you actually have the dependency)? > * Does the wording of the #warning need to be better - any suggestions > for future patches? I must have done something wrong, built only the drivers/staging/udlfb/ directory or something, with a full kernel build I no longer see this issue. Very sorry for the noise, and thanks for the full response. greg k-h _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
