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[2001:14ba:a073:af00:264b:feff:fe8b:be8a]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5b46cfa0e5esm821205e87.25.2026.08.17.19.24.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Aug 2026 19:24:46 -0700 (PDT) Date: Tue, 18 Aug 2026 05:24:44 +0300 From: Dmitry Baryshkov To: Chaoyi Chen Cc: Yongxing Mou , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Kevin Hilman , Jerome Brunet , Martin Blumenstingl , Rob Clark , Dmitry Baryshkov , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , Tomi Valkeinen , Bjorn Andersson , Konrad Dybcio , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-amlogic@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org Subject: Re: [PATCH 1/5] drm/bridge: allow hpd_notify() to suppress connector hotplug events Message-ID: <4qc3n3mwsonpzfxi3z2supslvlyat32xgsn7bnrstudtpitwri@enwxj4pkjexa> References: <20260629-msm-dp-msttypec-v1-0-646a10256233@oss.qualcomm.com> <20260629-msm-dp-msttypec-v1-1-646a10256233@oss.qualcomm.com> <364f223e-15c6-44c4-a909-134754cfd0e1@rock-chips.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <364f223e-15c6-44c4-a909-134754cfd0e1@rock-chips.com> X-Authority-Analysis: v=2.4 cv=Ua9hjqSN c=1 sm=1 tr=0 ts=6a83c271 cx=c_pps a=EVbN6Ke/fEF3bsl7X48z0g==:117 a=xqWC_Br6kY4A:10 a=kj9zAlcOel0A:10 a=Sv0fKeRqtYgA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=_K5XuSEh1TEqbUxoQ0s3:22 a=VwQbUJbxAAAA:8 a=QX4gbG5DAAAA:8 a=busZWuwHVHLsb9-ZDGQA:9 a=CjuIK1q_8ugA:10 a=a_PwQJl-kcHnX1M80qC6:22 a=AbAUZ8qAyYyZVLSsDulk:22 X-Proofpoint-GUID: YjPOwVG9C_Sy11GUcBwO9haWFtcUnGww X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODE4MDAxNSBTYWx0ZWRfX72N1BR5VTxMu 8GxDXbT67xJfNgCm1fQuDoX2nLD5DU2oVY6M4yaQ7sXN2HuX2oFvFwSI42ifHP40840PxsPuidj AeSgwwdNNOQAwjOB+JouxL6993nazxKRGopg4XlESUr5hjRiGPaAhQzCQiwtVWBo3guN6rO5b1S 2l8sdv2b4QAbCeEcKox3JM0p4P3299VPSqSpuZzsj1g47oS9PMg4+qzSPZzQWxPSv87+l7oO5Cy lCpOre/u/vt9xRCJrxMK8TTBReMzKEnRn26TJoZSLPzjfkFa9Ca1k3u49trmHNqaD/NxWqeKJVf Pg0Zz/6YHsJOi3edu2OpGsI3AVy0CQxju/A530MhYl/FdAq8eeP3ADp5WA5b4/IhG0bNw6Xinr3 5Q6xQHFowTYVyD6xYX/8a89QuB/lIBXocdd9jmE5Fq/r5FTkfTZgoaTDNasiCorwm9+inOyPKCq t0/WCVJNRLWH3O280Wg== X-Proofpoint-Spam-Info: AW1haW4tMjYwODE4MDAxNSBTYWx0ZWRfXyj1fwPwmYpnv 9GHzZ1clfHLOoQCkAAY13tbV92id29pjZ0SDpVHcnJUZg1QOUIqmimAdRjGcR9BXPgTKk5wcwBQ ODuoa1IEZDIVCwNXxcaw9GZSniIztJU= X-Proofpoint-ORIG-GUID: YjPOwVG9C_Sy11GUcBwO9haWFtcUnGww X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-17_04,2026-08-12_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 adultscore=0 priorityscore=1501 malwarescore=0 suspectscore=0 impostorscore=0 bulkscore=0 lowpriorityscore=0 phishscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608180015 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260817_192449_741912_195063A3 X-CRM114-Status: GOOD ( 24.32 ) X-BeenThere: linux-amlogic@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+linux-amlogic=archiver.kernel.org@lists.infradead.org On Tue, Aug 18, 2026 at 10:05:30AM +0800, Chaoyi Chen wrote: > Hello Yongxing, > > On 6/29/2026 10:48 PM, Yongxing Mou wrote: > > The bridge connector framework currently invokes all bridge > > hpd_notify() callbacks and unconditionally emits a connector hotplug > > event afterwards. > > > > However, not every HPD notification requires a userspace hotplug event. > > > > In particular, DP MST bridges may use hpd_notify() to propagate HPD and > > IRQ notifications through the bridge chain while the actual hotplug > > handling is performed by the DRM DP MST core. Connector creation, > > removal and userspace hotplug events are already managed by the MST > > topology framework. > > > > Allow hpd_notify() implementations to suppress the bridge connector > > hotplug event by introducing a bool *send_hotplug parameter. Drivers > > can clear this flag when HPD processing should not result in a > > connector hotplug notification. > > > > A NULL pointer indicates that hotplug suppression is not supported by > > the caller, such as the connector detect polling path. > > > > Should we add an API to distinguish between regular HPD events and > the IRQ-only notifications you mentioned? It well might be so, rendering the first series listed as a dependency as invalid (then it's good that we didn't land it up to now). I have been torn between adding a new API and extending the HPD events. I ended up choosing the latter one, but I might be wrong :-) My idea was that both USB-C AltModes and native DP deliver both mechanisms in the same way. If we add a separate API, we have to take care of possible interactions between those two (i.e. how should we react to IRQ_HPD, if we already have a HPD event being processed in flight)? > > I've recently seen similar approaches. For example, this patch[0] adds > handling for internal events, which I think is somewhat similar to the > IRQ-only notification here. > > [0]: https://lore.kernel.org/all/20260806-synopsys-dw-dp-improvements-v11-11-0d508505f383@collabora.com/ Thanks for the reminder about this series. I need to review it. -- With best wishes Dmitry _______________________________________________ linux-amlogic mailing list linux-amlogic@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-amlogic