From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from anholt.net ([50.246.234.109]:52050 "EHLO anholt.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752032AbdA0Vzy (ORCPT ); Fri, 27 Jan 2017 16:55:54 -0500 From: Eric Anholt To: Greg Kroah-Hartman Cc: devel@driverdev.osuosl.org, linux-media@vger.kernel.org, Mauro Carvalho Chehab , linux-rpi-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Eric Anholt Subject: [PATCH 4/6] staging: bcm2835-v4l2: Add a TODO file for improvements we need. Date: Fri, 27 Jan 2017 13:55:01 -0800 Message-Id: <20170127215503.13208-5-eric@anholt.net> In-Reply-To: <20170127215503.13208-1-eric@anholt.net> References: <20170127215503.13208-1-eric@anholt.net> Sender: linux-media-owner@vger.kernel.org List-ID: Signed-off-by: Eric Anholt --- drivers/staging/media/platform/bcm2835/TODO | 39 +++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 drivers/staging/media/platform/bcm2835/TODO diff --git a/drivers/staging/media/platform/bcm2835/TODO b/drivers/staging/media/platform/bcm2835/TODO new file mode 100644 index 000000000000..61a509992b9a --- /dev/null +++ b/drivers/staging/media/platform/bcm2835/TODO @@ -0,0 +1,39 @@ +1) Support dma-buf memory management. + +In order to zero-copy import camera images into the 3D or display +pipelines, we need to export our buffers through dma-buf so that the +vc4 driver can import them. This may involve bringing in the VCSM +driver (which allows long-term management of regions of memory in the +space that the VPU reserved and Linux otherwise doesn't have access +to), or building some new protocol that allows VCSM-style management +of Linux's CMA memory. + +2) Avoid extra copies for padding of images. + +We expose V4L2_PIX_FMT_* formats that have a specified stride/height +padding in the V4L2 spec, but that padding doesn't match what the +hardware can do. If we exposed the native padding requirements +through the V4L2 "multiplanar" formats, the firmware would have one +less copy it needed to do. + +3) Port to ARM64 + +The bulk_receive() does some manual cache flushing that are 32-bit ARM +only, which we should convert to proper cross-platform APIs. + +4) Convert to be a platform driver. + +Right now when the module probes, it tries to initialize VCHI and +errors out if it wasn't ready yet. If bcm2835-v4l2 was built in, then +VCHI generally isn't ready because it depends on both the firmware and +mailbox drivers having already loaded. + +We should have VCHI create a platform device once it's initialized, +and have this driver bind to it, so that we automatically load the +v4l2 module after VCHI loads. + +5) Drop the gstreamer workaround. + +This was a temporary workaround for a bug that was fixed mid-2014, and +we should remove it before stabilizing the driver. + -- 2.11.0