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Thu, 09 Jan 2025 04:14:23 -0800 (PST) Received: from linaro.org ([86.121.162.10]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-436e2da6401sm53853955e9.2.2025.01.09.04.14.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Jan 2025 04:14:23 -0800 (PST) Date: Thu, 9 Jan 2025 14:14:21 +0200 From: Abel Vesa To: Bjorn Andersson Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Karol Herbst , Lyude Paul , Danilo Krummrich , Jani Nikula , Rodrigo Vivi , Joonas Lahtinen , Tvrtko Ursulin , Rob Clark , Abhinav Kumar , Dmitry Baryshkov , Sean Paul , Marijn Suijten , Konrad Dybcio , Johan Hovold , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, nouveau@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, Johan Hovold Subject: Re: [PATCH v4 1/4] drm/dp: Add helper to set LTTPRs in transparent mode Message-ID: References: <20250108-drm-dp-msm-add-lttpr-transparent-mode-set-v4-0-918949bc2e3a@linaro.org> <20250108-drm-dp-msm-add-lttpr-transparent-mode-set-v4-1-918949bc2e3a@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On 25-01-08 16:17:47, Bjorn Andersson wrote: > On Wed, Jan 08, 2025 at 04:31:43PM +0200, Abel Vesa wrote: > > According to the DisplayPort standard, LTTPRs have two operating > > modes: > > - non-transparent - it replies to DPCD LTTPR field specific AUX > > requests, while passes through all other AUX requests > > - transparent - it passes through all AUX requests. > > > > Switching between this two modes is done by the DPTX by issuing > > an AUX write to the DPCD PHY_REPEATER_MODE register. > > > > Add a generic helper that allows switching between these modes. > > > > Also add a generic wrapper for the helper that handles the explicit > > disabling of non-transparent mode and its disable->enable sequence > > mentioned in the DP Standard v2.0 section 3.6.6.1. Do this in order > > to move this handling out of the vendor specific driver implementation > > into the generic framework. > > > > Tested-by: Johan Hovold > > Reviewed-by: Dmitry Baryshkov > > Reviewed-by: Johan Hovold > > Signed-off-by: Abel Vesa > > --- > > drivers/gpu/drm/display/drm_dp_helper.c | 62 +++++++++++++++++++++++++++++++++ > > include/drm/display/drm_dp_helper.h | 2 ++ > > 2 files changed, 64 insertions(+) > > > > diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c > > index da3c8521a7fa7d3c9761377363cdd4b44ab1106e..fa7eff94d408718a1762834597f0cd51376d2596 100644 > > --- a/drivers/gpu/drm/display/drm_dp_helper.c > > +++ b/drivers/gpu/drm/display/drm_dp_helper.c > > @@ -2817,6 +2817,68 @@ int drm_dp_lttpr_max_link_rate(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]) > > } > > EXPORT_SYMBOL(drm_dp_lttpr_max_link_rate); > > > > +/** > > + * drm_dp_lttpr_set_transparent_mode - set the LTTPR in transparent mode > > kernel-doc functions should have () suffix Yes, will add. > > > + * @aux: DisplayPort AUX channel > > + * @enable: Enable or disable transparent mode > > + * > > + * Returns 0 on success or a negative error code on failure. > > And this should be "Return: ...". Will fix as well. > > > + */ > > +int drm_dp_lttpr_set_transparent_mode(struct drm_dp_aux *aux, bool enable) > > +{ > > + u8 val = enable ? DP_PHY_REPEATER_MODE_TRANSPARENT : > > + DP_PHY_REPEATER_MODE_NON_TRANSPARENT; > > + int ret = drm_dp_dpcd_writeb(aux, DP_PHY_REPEATER_MODE, val); > > + > > + if (ret < 0) > > + return ret; > > + > > + return (ret == 1) ? 0 : -EIO; > > +} > > +EXPORT_SYMBOL(drm_dp_lttpr_set_transparent_mode); > > + > > +/** > > + * drm_dp_lttpr_init - init LTTPR transparency mode according to DP standard > > + * > > Documentation also explicitly says not to leave a blank line here... Will drop the blank line. > > Regards, > Bjorn > Thanks for reviewing! Abel