Re: [RFC PATCH 5/6] drm/msm/dsi: Flip greater-than check for slice_count and slice_per_intf

From: Konrad Dybcio <konrad.dybcio@linaro.org>
To: Marijn Suijten <marijn.suijten@somainline.org>,
	phone-devel@vger.kernel.org, Rob Clark <robdclark@gmail.com>,
	Abhinav Kumar <quic_abhinavk@quicinc.com>,
	Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
	Vinod Koul <vkoul@kernel.org>
Cc: ~postmarketos/upstreaming@lists.sr.ht,
	"AngeloGioacchino Del Regno"
	<angelogioacchino.delregno@somainline.org>,
	"Konrad Dybcio" <konrad.dybcio@somainline.org>,
	"Martin Botka" <martin.botka@somainline.org>,
	"Jami Kettunen" <jami.kettunen@somainline.org>,
	"Sean Paul" <sean@poorly.run>, "David Airlie" <airlied@gmail.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Stephen Boyd" <swboyd@chromium.org>,
	"Bjorn Andersson" <andersson@kernel.org>,
	"Jessica Zhang" <quic_jesszhan@quicinc.com>,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
	"Kuogee Hsieh" <quic_khsieh@quicinc.com>,
	"Jani Nikula" <jani.nikula@intel.com>,
	sunliming <sunliming@kylinos.cn>,
	"Sam Ravnborg" <sam@ravnborg.org>,
	"Haowen Bai" <baihaowen@meizu.com>,
	"Loic Poulain" <loic.poulain@linaro.org>,
	"Vinod Polimera" <quic_vpolimer@quicinc.com>,
	"Douglas Anderson" <dianders@chromium.org>,
	"Vladimir Lypak" <vladimir.lypak@gmail.com>,
	linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
	freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 5/6] drm/msm/dsi: Flip greater-than check for slice_count and slice_per_intf
Date: Wed, 14 Dec 2022 01:02:14 +0100	[thread overview]
Message-ID: <c5e33d9f-0dc4-fdd2-244a-3d463be1c4e8@linaro.org> (raw)
In-Reply-To: <20221213232207.113607-6-marijn.suijten@somainline.org>


On 14.12.2022 00:22, Marijn Suijten wrote:
> According to downstream /and the comment copied from it/ this comparison
> should be the other way around.  In other words, when the panel driver
> requests to use more slices per packet than what could be sent over this
> interface, it is bumped down to only use a single slice per packet (and
> strangely not the number of slices that could fit on the interface).
> 
> Fixes: 08802f515c3c ("drm/msm/dsi: Add support for DSC configuration")
> ---
Missing s-o-b

>  drivers/gpu/drm/msm/dsi/dsi_host.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 0686c35a6fd4..9bdfa0864cdf 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -855,11 +855,11 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod
>  	 */
>  	slice_per_intf = DIV_ROUND_UP(hdisplay, dsc->slice_width);
>  
> -	/* If slice_per_pkt is greater than slice_per_intf
> +	/* If slice_count is greater than slice_per_intf
>  	 * then default to 1. This can happen during partial
>  	 * update.
>  	 */
> -	if (slice_per_intf > dsc->slice_count)
> +	if (dsc->slice_count > slice_per_intf)
>  		dsc->slice_count = 1;
>  
>  	total_bytes_per_intf = dsc->slice_chunk_size * slice_per_intf;