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Sat, 14 Nov 2026 07:09:15 -0800 (PST) Received: from arch.localdomain ([2409:8a2b:a08:f11::1003]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-379563e6b6dsm30427886eec.21.2026.11.14.07.09.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 14 Nov 2026 07:09:15 -0800 (PST) From: Jun Yan To: luca.ceresoli@bootlin.com Cc: Laurent.pinchart@ideasonboard.com, airlied@gmail.com, andrzej.hajda@intel.com, damon.ding@rock-chips.com, dri-devel@lists.freedesktop.org, heiko@sntech.de, jernej.skrabec@gmail.com, jerrysteve1101@gmail.com, jonas@kwiboo.se, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, neil.armstrong@linaro.org, rfoss@kernel.org, simona@ffwll.ch, tzimmermann@suse.de Subject: Re: [PATCH v3] drm/bridge: analogix_dp: use devm_phy_optional_get() for the DP PHY Date: Sat, 14 Nov 2026 23:09:07 +0800 Message-ID: <20261114150907.305160-1-jerrysteve1101@gmail.com> X-Mailer: git-send-email 2.56.0 In-Reply-To: References: X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261114_070917_030045_2B52C7ED X-CRM114-Status: GOOD ( 24.25 ) X-Spam-Score: -1.9 (-) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Hi Luca, > Hello, > > On Fri Nov 13, 2026 at 2:12 PM CET, Jun Yan wrote: > > Hi Damon, > > > >> You are right, this is really a valid concern. > >> > >> If CONFIG_GENERIC_PHY is disabled, the old code could still proceed and > >> keep the driver probing, while the new version would return an error > >> directly. > > > > -ENOSYS can only come from the !CONFIG_GENERIC_PHY stubs in > > include/linux/phy/phy.h; the real implementation in drivers/phy/phy-core.= > c > > never returns it. And the stub for the optional variant returns NULL, not > > -ENOSYS: > > > > static inline struct phy *devm_phy_optional_get(struct device *dev, > > const char *string) > > { > > return NULL; > > } > > > > So with CONFIG_GENERIC_PHY disabled the PHY is still treated as absent > > (NULL), exactly as the old -ENOSYS branch did. With CONFIG_GENERIC_PHY > > enabled, -ENOSYS cannot occur, devm_phy_optional_get() turns -ENODEV into > > NULL, and any other error is still propagated - same as the open-coded > > check. > > > >> It should be better to keep the -ENOSYS handling to preserve the > >> original behavior. > > > > Overall the behaviour is unchanged in both configurations, so no separate > > handling is needed. > > Thanks for the analysis! Cna you send a v4 with that explained in the > commit message, possibly in a more concise way, maybe with bullets for the > various CONFIG_GENERIC_PHY on/off cases or so, for readability? > Yes, I'll send a v4. > Reading it now, this v3 commit message kind of said the same things. but it > misled both me and Damon, so it's worth a clear explanation. > > Thanks! > > Luca Thanks, Jun