From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from lb1-smtp-cloud9.xs4all.net ([194.109.24.22]:46266 "EHLO lb1-smtp-cloud9.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932330AbeCIRNp (ORCPT ); Fri, 9 Mar 2018 12:13:45 -0500 Subject: Re: [PATCH v12 11/33] rcar-vin: set a default field to fallback on To: =?UTF-8?Q?Niklas_S=c3=b6derlund?= Cc: Laurent Pinchart , linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org, tomoharu.fukawa.eb@renesas.com, Kieran Bingham References: <20180307220511.9826-1-niklas.soderlund+renesas@ragnatech.se> <20180307220511.9826-12-niklas.soderlund+renesas@ragnatech.se> <4181fb92-5ac9-9ad8-a60d-65c57f5baaa0@xs4all.nl> <20180309161711.GI2205@bigcity.dyn.berto.se> <074a1f52-2faf-6025-58b2-364def833b80@xs4all.nl> <20180309170759.GJ2205@bigcity.dyn.berto.se> From: Hans Verkuil Message-ID: Date: Fri, 9 Mar 2018 18:13:43 +0100 MIME-Version: 1.0 In-Reply-To: <20180309170759.GJ2205@bigcity.dyn.berto.se> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org List-ID: On 09/03/18 18:07, Niklas Söderlund wrote: > Hi Hans, > > Thanks for your feedback. > > On 2018-03-09 17:28:39 +0100, Hans Verkuil wrote: >> On 09/03/18 17:17, Niklas Söderlund wrote: >>> Hi Hans, >>> >>> Thanks for your feedback, I don't think I can appreciate how happy I'm >>> that you reviewed this patch-set, Thank you! >> >> You're welcome! >> >>> >>> On 2018-03-09 16:25:23 +0100, Hans Verkuil wrote: >>>> On 07/03/18 23:04, Niklas Söderlund wrote: >>>>> If the field is not supported by the driver it should not try to keep >>>>> the current field. Instead it should set it to a default fallback. Since >>>>> trying a format should always result in the same state regardless of the >>>>> current state of the device. >>>>> >>>>> Signed-off-by: Niklas Söderlund >>>>> Reviewed-by: Laurent Pinchart >>>>> --- >>>>> drivers/media/platform/rcar-vin/rcar-v4l2.c | 9 +++------ >>>>> 1 file changed, 3 insertions(+), 6 deletions(-) >>>>> >>>>> diff --git a/drivers/media/platform/rcar-vin/rcar-v4l2.c b/drivers/media/platform/rcar-vin/rcar-v4l2.c >>>>> index c2265324c7c96308..ebcd78b1bb6e8cb6 100644 >>>>> --- a/drivers/media/platform/rcar-vin/rcar-v4l2.c >>>>> +++ b/drivers/media/platform/rcar-vin/rcar-v4l2.c >>>>> @@ -23,6 +23,7 @@ >>>>> #include "rcar-vin.h" >>>>> >>>>> #define RVIN_DEFAULT_FORMAT V4L2_PIX_FMT_YUYV >>>>> +#define RVIN_DEFAULT_FIELD V4L2_FIELD_NONE >>>>> >>>>> /* ----------------------------------------------------------------------------- >>>>> * Format Conversions >>>>> @@ -143,7 +144,7 @@ static int rvin_reset_format(struct rvin_dev *vin) >>>>> case V4L2_FIELD_INTERLACED: >>>>> break; >>>>> default: >>>>> - vin->format.field = V4L2_FIELD_NONE; >>>>> + vin->format.field = RVIN_DEFAULT_FIELD; >>>>> break; >>>>> } >>>>> >>>>> @@ -213,10 +214,6 @@ static int __rvin_try_format(struct rvin_dev *vin, >>>>> u32 walign; >>>>> int ret; >>>>> >>>>> - /* Keep current field if no specific one is asked for */ >>>>> - if (pix->field == V4L2_FIELD_ANY) >>>>> - pix->field = vin->format.field; >>>>> - >>>>> /* If requested format is not supported fallback to the default */ >>>>> if (!rvin_format_from_pixel(pix->pixelformat)) { >>>>> vin_dbg(vin, "Format 0x%x not found, using default 0x%x\n", >>>>> @@ -246,7 +243,7 @@ static int __rvin_try_format(struct rvin_dev *vin, >>>>> case V4L2_FIELD_INTERLACED: >>>>> break; >>>>> default: >>>>> - pix->field = V4L2_FIELD_NONE; >>>>> + pix->field = RVIN_DEFAULT_FIELD; >>>>> break; >>>>> } >>>>> >>>>> >>>> >>>> I wonder if this code is correct. What if the adv7180 is the source? Does that even >>>> support FIELD_NONE? I suspect that the default field should actually depend on the >>>> source. FIELD_NONE for dv_timings based or sensor based subdevs and FIELD_INTERLACED >>>> for SDTV (g/s_std) subdevs. >>> >>> I see what you mean but I think this is correct. The field is only set >>> to V4L2_FIELD_NONE if the field returned from the source is not one of >>> TOP, BOTTOM, ALTERNATE, NONE, INERLACED, INTERLACED_TB, INTERLACED_BT. >>> So it works perfectly with the adv7180 as it will return >>> V4L2_FIELD_INTERLACED and then VIN will accept that and not change it. >>> So the field do depend on the source both before and after this change. >> >> Is it? If I pass FIELD_ANY to VIDIOC_TRY_FMT then that is passed to the >> adv7180 via __rvin_try_format and __rvin_try_format_source. But >> __rvin_try_format_source puts back the old field value after calling >> set_fmt for the adv7180 (pix->field = field). >> >> So pix->field is still FIELD_ANY when it enters the switch and so falls >> into the default case and it becomes FIELD_NONE. >> >> What's weird is the 'pix->field = field' in __rvin_try_format_source(). >> Could that be a bug? Without that line what you say here would be correct. > > Ahh yes, you are correct. I did not see this as I handle this in a later > patch in the series '[PATCH v12 16/33] rcar-vin: simplify how formats > are set and reset': > > + if (field != V4L2_FIELD_ANY) > + pix->field = field; > > - pix->field = field; > > If I move this change to this patch do you think that would address your > concern? Yes, that would make a lot more sense. After making that change you can add my: Reviewed-by: Hans Verkuil to this patch. Regards, Hans The intent is that if V4L2_FIELD_ANY is requested by the user > it should get what the source provides but I still like to allow for the > user to request a specific field format. For example in follow up > patches to this series I add SEQ_TB/BT and the user might want to > request to receive frames in that format. > >> >> Regards, >> >> Hans >> >>> >>> This check is just to block the driver reporting SEQ_TB/BT if a source >>> where to report that (I known of no source who reports that) to >>> userspace as the driver do not yet support this. I have patches to add >>> support for this but I will keep them back until this series are picked >>> up :-) >>> >>>> >>>> I might very well be missing something here but it looks suspicious. >>>> >>>> Regards, >>>> >>>> Hans >>> >> >