From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756805AbdCXLYe (ORCPT ); Fri, 24 Mar 2017 07:24:34 -0400 Received: from aer-iport-3.cisco.com ([173.38.203.53]:21096 "EHLO aer-iport-3.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751421AbdCXLYZ (ORCPT ); Fri, 24 Mar 2017 07:24:25 -0400 X-IronPort-AV: E=Sophos;i="5.36,214,1486425600"; d="scan'208";a="651673254" Subject: Re: [PATCH 0/3] Handling of reduced FPS in V4L2 To: Jose Abreu , linux-media@vger.kernel.org References: <1939bd77-a74d-3ad6-06db-2b1eaa205aca@synopsys.com> Cc: Carlos Palminha , Mauro Carvalho Chehab , Hans Verkuil , linux-kernel@vger.kernel.org From: Hans Verkuil Message-ID: <3a7b5c81-834c-8d1e-2181-6d8f57d20f7b@cisco.com> Date: Fri, 24 Mar 2017 12:24:22 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 MIME-Version: 1.0 In-Reply-To: <1939bd77-a74d-3ad6-06db-2b1eaa205aca@synopsys.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Authenticated-User: hansverk Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/24/17 12:03, Jose Abreu wrote: > Hi Hans, > > > On 21-03-2017 11:49, Jose Abreu wrote: >> Hi all, >> >> This is a follow up patch from this discussion [1]. It should be >> seen more as a starting point to introduce better handling of >> time per frame in v4l2. Quoting Hans Verkuil from [1]: >> >> 1) "Add a flag V4L2_DV_FL_CAN_DETECT_REDUCED_FPS. If set, >> then the hw can detect the difference between regular fps >> and 1000/1001 fps. Note: this is only valid for timings of >> VIC codes with the V4L2_DV_FL_CAN_REDUCE_FPS flag set." >> >> 2) "Allow V4L2_DV_FL_REDUCED_FPS to be used for receivers >> if V4L2_DV_FL_CAN_DETECT_REDUCED_FPS is set." >> >> 3) "For standard VIC codes the pixelclock returned by >> query_dv_timings is that of the corresponding VIC timing, >> not what is measured. This will ensure fixed fps values" >> >> 4) "g_parm should calculate the fps based on the v4l2_bt_timings >> struct, looking at the REDUCES_FPS flags. For those receivers that >> cannot detect the difference, the fps will be 24/30/60 Hz, for >> those that can detect the difference g_parm can check if both >> V4L2_DV_FL_CAN_DETECT_REDUCED_FPS and V4L2_DV_FL_REDUCED_FPS are >> set and reduce the fps by 1000/1001." >> >> ----------- >> In terms of implementation: >> - Point 1) is done in patch 1/3 >> - Point 2) and 3) should be done by a HDMI Receiver driver >> (I think?). >> - Point 4) is done in patch 2/3. >> - The patch 3/3 is a simple implementation (which was not >> tested) in the cobalt driver >> ----------- >> >> [1] https://patchwork.kernel.org/patch/9609441/ >> >> Best regards, >> Jose Miguel Abreu >> >> Cc: Carlos Palminha >> Cc: Mauro Carvalho Chehab >> Cc: Hans Verkuil >> Cc: linux-media@vger.kernel.org >> Cc: linux-kernel@vger.kernel.org >> >> Jose Abreu (3): >> [media] videodev2.h: Add new DV flag CAN_DETECT_REDUCED_FPS >> [media] v4l2-dv-timings: Introduce v4l2_calc_timeperframe helper >> [media] cobalt: Use v4l2_calc_timeperframe helper >> >> drivers/media/pci/cobalt/cobalt-v4l2.c | 9 +++++-- >> drivers/media/v4l2-core/v4l2-dv-timings.c | 39 +++++++++++++++++++++++++++++++ >> include/media/v4l2-dv-timings.h | 11 +++++++++ >> include/uapi/linux/videodev2.h | 7 ++++++ >> 4 files changed, 64 insertions(+), 2 deletions(-) >> > > Can you please review this series, when possible? And if you > could test it on cobalt it would be great :) Hopefully next week. Did you have some real-world numbers w.r.t. measured pixelclock frequencies and 60 vs 59.94 Hz and 24 vs 23.976 Hz? I do want to see that, since this patch series only makes sense if you can actually make use of it to reliably detect the difference. I will try to test that myself with cobalt, but almost certainly I won't be able to tell the difference; if memory serves it can't detect the freq with high enough precision. Regards, Hans