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[82.37.195.13]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-42cb7fba20esm40814603f8f.37.2025.11.26.06.20.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Nov 2025 06:20:24 -0800 (PST) Date: Wed, 26 Nov 2025 14:20:22 +0000 From: Daniel Thompson To: Thomas Zimmermann Cc: Daniel Thompson , Doug Anderson , simona@ffwll.ch, airlied@gmail.com, alexander.deucher@amd.com, christian.koenig@amd.com, lyude@redhat.com, dakr@kernel.org, deller@gmx.de, mripard@kernel.org, maarten.lankhorst@linux.intel.com, jason.wessel@windriver.com, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Nir Lichtman Subject: Re: [PATCH 0/5] drm: Remove remaining support for kdb Message-ID: References: <20251125130634.1080966-1-tzimmermann@suse.de> <054f60ca-b898-488f-81f4-14eed0a1360b@suse.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <054f60ca-b898-488f-81f4-14eed0a1360b@suse.de> On Wed, Nov 26, 2025 at 02:32:32PM +0100, Thomas Zimmermann wrote: > Hi > > Am 26.11.25 um 13:19 schrieb Daniel Thompson: > > On Tue, Nov 25, 2025 at 07:26:33AM -0800, Doug Anderson wrote: > > > On Tue, Nov 25, 2025 at 5:06 AM Thomas Zimmermann wrote: > > > > > > > > Therefore remove the remaining support for kdb from the DRM drivers > > > > and from DRM fbdev emulation. Also remove the hooks from fbdev, as > > > > there are no fbdev drivers with kdb support. > > > > > > > > If we ever want to address kdb support within DRM drivers, a place to > > > > start would be the scanout buffers used by DRM's panic screen. These > > > > use the current display mode. They can be written and flushed without > > > > mode setting involved. > > > > > > > > Note: kdb over serial lines is not affected by this series and continues > > > > to work as before. > > > > > > > > Thomas Zimmermann (5): > > > > drm/amdgpu: Do not implement mode_set_base_atomic callback > > > > drm/nouveau: Do not implement mode_set_base_atomic callback > > > > drm/radeon: Do not implement mode_set_base_atomic callback > > > > drm/fbdev-helper: Remove drm_fb_helper_debug_enter/_leave() > > > > fbcon: Remove fb_debug_enter/_leave from struct fb_ops > > > Personally, I've never worked with kdb over anything other than > > > serial, so this won't bother any of my normal workflows. That being > > > said, at least as of a year ago someone on the lists was talking about > > > using kdb with a keyboard and (presumably) a display. You can see a > > > thread here: > > > > > > http://lore.kernel.org/r/20241031192350.GA26688@lichtman.org > > > > > > Daniel may also have comments here? > > TL;DR - I'm pretty relaxed about these changes... but I'd like > > to know how to test the changes. > > > > Like Doug I only really use kdb via serial but, since I'm maintain > > the thing I do occasionally test kdb works on the qemu console. I don't > > do it very often though because it's a manual test! > > > > I'd assume that will still work since it won't involve any of the > > drivers above. I'm afraid I can't double check that since patch 4 > > doesn't apply cleanly in v6.18-rc7 (nor to linux-next... and neither > > does the base-commit appear in linux-next). > > To test its effects, ignore this series and simply clear the two calbacks at > [1]. This is where the debugger invokes fbcon. The series removes their > implementation in the final patch. > > [1] https://elixir.bootlin.com/linux/v6.17.9/source/drivers/video/fbdev/core/fbcon.c#L3202 Thanks. Explanation in original cover letter was great and there's certainly been no harm to QEMU. Acked-by: Daniel Thompson (RISCstar) Daniel.