Kieran Bingham
1054080d29
[ Upstream commitdd844fb8e5] Enabling CONFIG_DMA_API_DEBUG=y and CONFIG_DMA_API_DEBUG_SG=y will enable extra validation on DMA operations ensuring that the size restraints are met. When using the FCP in conjunction with the VSP1/DU, and display frames, the size of the DMA operations is larger than the default maximum segment size reported by the DMA core (64K). With the DMA debug enabled, this produces a warning such as the following: "DMA-API: rcar-fcp fea27000.fcp: mapping sg segment longer than device claims to support [len=3145728] [max=65536]" We have no specific limitation on the segment size which isn't already handled by the VSP1/DU which actually handles the DMA allcoations and buffer management, so define a maximum segment size of up to 4GB (a 32 bit mask). Reported-by: Geert Uytterhoeven <geert+renesas@glider.be> Fixes:7b49235e83("[media] v4l: Add Renesas R-Car FCP driver") Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.