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[92.176.231.205]) by smtp.gmail.com with ESMTPSA id g19-20020a05600c4ed300b0039c4506bd25sm24810750wmq.14.2022.06.09.07.28.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 09 Jun 2022 07:28:22 -0700 (PDT) Message-ID: <66dc8d78-ccd3-ac21-644d-26b8d20ba791@redhat.com> Date: Thu, 9 Jun 2022 16:28:20 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH v6 0/5] Fix some races between sysfb device registration and drivers probe To: linux-kernel@vger.kernel.org References: <20220607182338.344270-1-javierm@redhat.com> From: Javier Martinez Canillas In-Reply-To: <20220607182338.344270-1-javierm@redhat.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=javierm@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-fbdev@vger.kernel.org, kvm@vger.kernel.org, Jonathan Corbet , Greg Kroah-Hartman , Helge Deller , linux-doc@vger.kernel.org, dri-devel@lists.freedesktop.org, Hans de Goede , Alex Williamson , Peter Jones , Gerd Hoffmann , Thomas Zimmermann , Daniel Vetter , Laszlo Ersek Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 6/7/22 20:23, Javier Martinez Canillas wrote: > The patches in this series contain mostly changes suggested by Daniel Vetter > Thomas Zimmermann. They aim to fix existing races between the Generic System > Framebuffer (sysfb) infrastructure and the fbdev and DRM device registration. > > For example, it is currently possible for sysfb to register a platform > device after a real DRM driver was registered and requested to remove the > conflicting framebuffers. Or is possible for a simple{fb,drm} to match with > a device previously registered by sysfb, even after a real driver is present. > > A symptom of this issue, was worked around with the commit fb561bf9abde > ("fbdev: Prevent probing generic drivers if a FB is already registered") > but that's really a hack and should be reverted instead. > > This series attempt to fix it more correctly and revert the mentioned hack. > That will also allow to make the num_registered_fb variable not visible to > drivers anymore, since that's internal to fbdev core. > Pushed patches 1-4 to drm-misc (drm-misc-next). Thanks! -- Best regards, Javier Martinez Canillas Linux Engineering Red Hat