Thierry Reding
631090e155
The DRM_IOCTL_MODE_CREATE_DUMB (and others) IOCTL isn't very rigorously specified, which has the effect that some kernel drivers do not consider the .pitch and .size fields of struct drm_mode_create_dumb outputs only. Instead they will use these as lower bounds and overwrite them only if the values that they compute are larger than what userspace provided. This works if and only if userspace initializes the fields explicitly to either 0 or some meaningful value. However, if userspace just leaves the values uninitialized and the struct drm_mode_create_dumb is allocated on the stack for example, the driver may try to overallocate buffers. Fortunately most userspace does zero out the structure before passing it to the IOCTL, but there are rare exceptions. Mesa is one of them. In an attempt to rectify this situation, kernel drivers are being updated to not use the .pitch and .size fields as inputs. However in order to fix the issue with older kernels, make sure that Mesa always zeros out the structure as well. Future IOCTLs should be more rigorously defined so that structures can be validated and IOCTLs rejected if output fields aren't set to zero. Signed-off-by: Thierry Reding <treding@nvidia.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
File: docs/README.WIN32 Last updated: 21 June 2013 Quick Start ----- ----- Windows drivers are build with SCons. Makefiles or Visual Studio projects are no longer shipped or supported. Run scons osmesa mesagdi to build classic mesa Windows GDI drivers; or scons libgl-gdi to build gallium based GDI driver. This will work both with MSVS or Mingw. Windows Drivers ------- ------- At this time, only the gallium GDI driver is known to work. Source code also exists in the tree for other drivers in src/mesa/drivers/windows, but the status of this code is unknown. Recipe ------ Building on windows requires several open-source packages. These are steps that work as of this writing. - install python 2.7 - install scons (latest) - install mingw, flex, and bison - install pywin32 from here: http://www.lfd.uci.edu/~gohlke/pythonlibs get pywin32-218.4.win-amd64-py2.7.exe - install git - download mesa from git see http://www.mesa3d.org/repository.html - run scons General ------- After building, you can copy the above DLL files to a place in your PATH such as $SystemRoot/SYSTEM32. If you don't like putting things in a system directory, place them in the same directory as the executable(s). Be careful about accidentially overwriting files of the same name in the SYSTEM32 directory. The DLL files are built so that the external entry points use the stdcall calling convention. Static LIB files are not built. The LIB files that are built with are the linker import files associated with the DLL files. The si-glu sources are used to build the GLU libs. This was done mainly to get the better tessellator code. If you have a Windows-related build problem or question, please post to the mesa-dev or mesa-users list.