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Thu, 27 Feb 2025 09:25:32 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id F0ysNowvwGcbEwAAD6G6ig (envelope-from ); Thu, 27 Feb 2025 09:25:32 +0000 Message-ID: Date: Thu, 27 Feb 2025 10:25:32 +0100 Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/3] dummycon: only build module if there are users To: Arnd Bergmann , Arnd Bergmann , Greg Kroah-Hartman , Helge Deller Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20250225164436.56654-1-arnd@kernel.org> <4d047af3-fd30-4fa4-aa3d-c0359856d750@suse.de> <29ecc7c4-2887-4989-a1d3-aa76b44c0387@suse.de> <79d35e3b-9a0d-41a5-ab07-797bfa1e19cb@app.fastmail.com> Content-Language: en-US From: Thomas Zimmermann Autocrypt: addr=tzimmermann@suse.de; keydata= xsBNBFs50uABCADEHPidWt974CaxBVbrIBwqcq/WURinJ3+2WlIrKWspiP83vfZKaXhFYsdg XH47fDVbPPj+d6tQrw5lPQCyqjwrCPYnq3WlIBnGPJ4/jreTL6V+qfKRDlGLWFjZcsrPJGE0 BeB5BbqP5erN1qylK9i3gPoQjXGhpBpQYwRrEyQyjuvk+Ev0K1Jc5tVDeJAuau3TGNgah4Yc hdHm3bkPjz9EErV85RwvImQ1dptvx6s7xzwXTgGAsaYZsL8WCwDaTuqFa1d1jjlaxg6+tZsB 9GluwvIhSezPgnEmimZDkGnZRRSFiGP8yjqTjjWuf0bSj5rUnTGiyLyRZRNGcXmu6hjlABEB AAHNJ1Rob21hcyBaaW1tZXJtYW5uIDx0emltbWVybWFubkBzdXNlLmRlPsLAjgQTAQgAOAIb AwULCQgHAgYVCgkICwIEFgIDAQIeAQIXgBYhBHIX+6yM6c9jRKFo5WgNwR1TC3ojBQJftODH AAoJEGgNwR1TC3ojx1wH/0hKGWugiqDgLNXLRD/4TfHBEKmxIrmfu9Z5t7vwUKfwhFL6hqvo lXPJJKQpQ2z8+X2vZm/slsLn7J1yjrOsoJhKABDi+3QWWSGkaGwRJAdPVVyJMfJRNNNIKwVb U6B1BkX2XDKDGffF4TxlOpSQzdtNI/9gleOoUA8+jy8knnDYzjBNOZqLG2FuTdicBXblz0Mf vg41gd9kCwYXDnD91rJU8tzylXv03E75NCaTxTM+FBXPmsAVYQ4GYhhgFt8S2UWMoaaABLDe 7l5FdnLdDEcbmd8uLU2CaG4W2cLrUaI4jz2XbkcPQkqTQ3EB67hYkjiEE6Zy3ggOitiQGcqp j//OwE0EWznS4AEIAMYmP4M/V+T5RY5at/g7rUdNsLhWv1APYrh9RQefODYHrNRHUE9eosYb T6XMryR9hT8XlGOYRwKWwiQBoWSDiTMo/Xi29jUnn4BXfI2px2DTXwc22LKtLAgTRjP+qbU6 3Y0xnQN29UGDbYgyyK51DW3H0If2a3JNsheAAK+Xc9baj0LGIc8T9uiEWHBnCH+RdhgATnWW GKdDegUR5BkDfDg5O/FISymJBHx2Dyoklv5g4BzkgqTqwmaYzsl8UxZKvbaxq0zbehDda8lv hFXodNFMAgTLJlLuDYOGLK2AwbrS3Sp0AEbkpdJBb44qVlGm5bApZouHeJ/+n+7r12+lqdsA EQEAAcLAdgQYAQgAIAIbDBYhBHIX+6yM6c9jRKFo5WgNwR1TC3ojBQJftOH6AAoJEGgNwR1T C3ojVSkIALpAPkIJPQoURPb1VWjh34l0HlglmYHvZszJWTXYwavHR8+k6Baa6H7ufXNQtThR yIxJrQLW6rV5lm7TjhffEhxVCn37+cg0zZ3j7zIsSS0rx/aMwi6VhFJA5hfn3T0TtrijKP4A SAQO9xD1Zk9/61JWk8OysuIh7MXkl0fxbRKWE93XeQBhIJHQfnc+YBLprdnxR446Sh8Wn/2D Ya8cavuWf2zrB6cZurs048xe0UbSW5AOSo4V9M0jzYI4nZqTmPxYyXbm30Kvmz0rYVRaitYJ 4kyYYMhuULvrJDMjZRvaNe52tkKAvMevcGdt38H4KSVXAylqyQOW5zvPc4/sq9c= In-Reply-To: <79d35e3b-9a0d-41a5-ab07-797bfa1e19cb@app.fastmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.30 X-Spamd-Result: default: False [-4.30 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; FREEMAIL_TO(0.00)[arndb.de,kernel.org,linuxfoundation.org,gmx.de]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; RCPT_COUNT_SEVEN(0.00)[7]; MIME_TRACE(0.00)[0:+]; MID_RHS_MATCH_FROM(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmx.de]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_TLS_ALL(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FUZZY_BLOCKED(0.00)[rspamd.com]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:mid] X-Spam-Flag: NO X-Spam-Level: Hi Am 26.02.25 um 12:46 schrieb Arnd Bergmann: > On Wed, Feb 26, 2025, at 09:16, Thomas Zimmermann wrote: >> Am 26.02.25 um 08:55 schrieb Arnd Bergmann: >> Here's another general question. vgacon and fbcon only seem usable with >> CONFIG_VT=y. Wouldn't it make sense to have them depend on CONFIG_VT=y? >> dummycon could then be implemented as part of the vt code, maybe even >> become a vt-internal thing. The console code is complex, so I'm probably >> missing something here? > I think in theory one may have a system use fbcon purely to get the > boot logo, but not actually support VT. I had also assumed there might > be a way to use fbcon as the console (i.e. printk) but not register > the tty, but it looks like the console code still requires vt. > > After I looked at the vt and conswitchp code some more, I wonder > if we could go the other way and instead of integrating it more > make the conswitchp logic optional: most of the complexity here > deals with switching between text console and fbcon dynamically, > but having any text console support is getting very rare (vga > on alpha/mips/x86-32, newport on mips-ip22, sti on parisc). > > If we do this, the conswitchp code could be merged with dummycon > in drivers/video/console, with the simpler alternative just > calling into fbcon functions. I'm not sure if we can already drop > vgacon from normal x86-64 distro configs, i.e. if there are cases > that are not already covered by any of efi-earlycon, efifb, > vga16fb, vesafb/uvesafb or a PCI DRM driver. Thanks for the lengthy answer. I don't want to add work to your todo list. For vgacon, I wouldn't remove it yet, as there still exisits x86_64 systems with plain VGA support. Best regards Thomas > > Arnd > -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstrasse 146, 90461 Nuernberg, Germany GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman HRB 36809 (AG Nuernberg)