From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Subject: Re: [PATCH v2 11/14] v4l: vsp1: Add support for header display lists in continuous mode Date: Tue, 01 Aug 2017 21:47:16 +0300 Message-ID: <3464715.HJz2XH12Bc@avalon> References: <20170626181226.29575-1-laurent.pinchart+renesas@ideasonboard.com> <20170626181226.29575-12-laurent.pinchart+renesas@ideasonboard.com> <5051664d-1793-2245-28cd-94334f847977@ideasonboard.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <5051664d-1793-2245-28cd-94334f847977@ideasonboard.com> Sender: linux-renesas-soc-owner@vger.kernel.org To: kieran.bingham@ideasonboard.com Cc: Laurent Pinchart , dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org List-Id: dri-devel@lists.freedesktop.org Hi Kieran, On Tuesday 01 Aug 2017 18:35:48 Kieran Bingham wrote: > On 26/06/17 19:12, Laurent Pinchart wrote: > > The VSP supports both header and headerless display lists. The latter is > > easier to use when the VSP feeds data directly to the DU in continuous > > mode, and the driver thus uses headerless display lists for DU operation > > and header display lists otherwise. > > > > Headerless display lists are only available on WPF.0. This has never > > been an issue so far, as only WPF.0 is connected to the DU. However, on > > H3 ES2.0, the VSP-DL instance has both WPF.0 and WPF.1 connected to the > > DU. We thus can't use headerless display lists unconditionally for DU > > operation. > > Would it be crazy to suggest we drop headerless display lists? > > If we must support header display lists in continuous mode - Rather than > having 2 cases for continuous modes to support (having to support > headerless, on WPF.0, and header on WPF.1) if we just use your header loop > trick - would that simplify our code maintenance? > > (We can always remove headerless support later if you agree, this is more of > an idea at the moment) I had the exact same thought, but I believe we should wait a few kernel releases to see if the next code is stable before removing the old one. I have a debug patch that forces usage of header display lists unconditionally, and I'll try to develop a few additional stress-tests for that. > > Implement support for continuous mode with header display lists, and use > > it for DU operation on WPF outputs that don't support headerless mode. > > > > Signed-off-by: Laurent Pinchart > > > > Except for future discussion points, I can't see anything wrong here so: > > Reviewed-by: Kieran Bingham > > > --- > > > > drivers/media/platform/vsp1/vsp1_dl.c | 195 +++++++++++++++++--------- > > drivers/media/platform/vsp1/vsp1_regs.h | 1 + > > 2 files changed, 127 insertions(+), 69 deletions(-) -- Regards, Laurent Pinchart