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([2a01:e0a:c:37e0:5b4d:4594:545c:dd8]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3b5e8e0d872sm14765473f8f.60.2025.07.15.01.57.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 15 Jul 2025 01:57:07 -0700 (PDT) Message-ID: <1961897d-cf42-4495-aec7-f4c20dfe7566@redhat.com> Date: Tue, 15 Jul 2025 10:57:04 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH drm-next] drm/bochs: Add support for drm_panic To: Askar Safin , ryasuoka@redhat.com Cc: airlied@gmail.com, dri-devel@lists.freedesktop.org, kraxel@redhat.com, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, simona@ffwll.ch, tzimmermann@suse.de, virtualization@lists.linux.dev References: <20250613132023.106946-1-ryasuoka@redhat.com> <20250714000456.14-1-safinaskar@zohomail.com> Content-Language: en-US, fr From: Jocelyn Falempe In-Reply-To: <20250714000456.14-1-safinaskar@zohomail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 14/07/2025 02:04, Askar Safin wrote: > Are normal panics (i. e. not drm panics) still supposed to work with bochs? "Normal panics", is just the console logs through fbcon. The problem is that this is not designed to work in a panic context, so on some driver it can work, but it's not reliable. Also depending on the panic source (Like if the panic occurs in IRQ context), you probably won't see anything. I think the regression is likely because the driver switched to use a shadow buffer (ie: fbcon draws to a buffer in system memory, which is copied to the "VRAM" in a workqueue, and workqueues are disabled in a panic context). So there is no easy fix for the fbcon panic. This patch series, only take care of DRM panic. You can get the same output as fbcon, by selecting CONFIG_DRM_PANIC_SCREEN"kmsg". -- Jocelyn > > If yes, then I want to point out that they, in fact, don't work since 2019. > I. e. panics are not shown in Qemu if: > 1) bochs is used > 2) we use "normal" panics (not drm panics) > > I already reported this here: https://lore.kernel.org/regressions/197f290e30b.eaadc7bc7913.7315623184036672946@zohomail.com/T/#u , > but nobody answered. > > -- > Askar Safin >