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Wed, 16 Sep 2026 11:40:21 +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 pHThNiSAqmrPKAAAD6G6ig (envelope-from ); Wed, 16 Sep 2026 11:40:21 +0000 Message-ID: Date: Wed, 16 Sep 2026 13:40:20 +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 v3 2/2] drm/tiny: add support for PIXPAPER 4.26 monochrome e-ink panel To: LiangCheng Wang , Devarsh Thakkar , Maarten Lankhorst , Maxime Ripard , David Airlie , Simona Vetter , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Wig Cheng , Neil Armstrong , Sam Ravnborg , Javier Martinez Canillas Cc: dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Tomi Valkeinen References: <20260529-bar-v3-0-5c2ac1c751ee@gmail.com> <20260529-bar-v3-2-5c2ac1c751ee@gmail.com> <2bfb73e6-dca3-4d93-af04-3c644929dd19@ti.com> <20260616083921.4066690-1-zaq14760@gmail.com> <423c3dca-9589-488d-8462-c3d51f05ee4a@ti.com> <20260617020926.114947-1-zaq14760@gmail.com> <8fcfab0f-6b98-478b-be4a-c5b810fb3524@ti.com> <20260731035705.3198816-1-zaq14760@gmail.com> <20260916082924.956116-1-zaq14760@gmail.com> <0a13ccb8-8817-4223-a4a2-0de594ac8c71@suse.de> <20260916094453.1062125-1-zaq14760@gmail.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: <20260916094453.1062125-1-zaq14760@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Score: -2.80 X-Spam-Level: X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; FREEMAIL_TO(0.00)[gmail.com,ti.com,linux.intel.com,kernel.org,ffwll.ch,linaro.org,ravnborg.org,redhat.com]; TAGGED_RCPT(0.00)[dt]; MIME_TRACE(0.00)[0:+]; RCPT_COUNT_TWELVE(0.00)[17]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; 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)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:url,imap1.dmz-prg2.suse.org:helo,suse.de:mid] X-Spam-Flag: NO (cc'ing Javier for ssd130x expertise) Hi Am 16.09.26 um 11:44 schrieb LiangCheng Wang: > Hi Thomas, > > Thank you for the quick reply. > >> Where exactly are these ssd16xx patches. I cannot find them in the DRM >> trees. I presume they are not upstream yet? > That is right, they are not upstream. Devarsh posted them on 1 May and > the series is still at v1 on the list: > > [PATCH 0/6] Add DRM driver for Solomon SSD16xx e-paper display controllers > https://lore.kernel.org/all/20260430183311.2978142-1-devarsht@ti.com/ > > One thing that is easy to miss, and that I should have made clearer in my > last mail: that v1 series covers the SSD1683 only. The SSD1677, which is > the controller on the PIXPAPER 4.26m, is not part of it. Devarsh has > SSD1677 support in a staged branch that he kindly shared with me in July, > and that is what I tested on the panel: > > https://github.com/devarsht/linux-next/commits/ssd16xx_7_2/ > > Those SSD1677 patches have not been posted to the list yet, which is why > the panel support has not had anything to build on so far. > >> If there's support for similar ICs, I'd strongly prefer to have the >> ssd1677 be part of that instead of a stand-alone driver. >> >> Once the stand-alone driver is in place, users will rely on it. Then it >> becomes hard to replace. We had (have?) cases where there are several >> drivers for the same hardware. > Understood, and thank you for explaining the reasoning - the point about > users coming to depend on a driver that is then hard to replace makes > sense, and I would rather not create that problem. I will drop the > standalone driver and add the PIXPAPER 4.26m to ssd16xx instead, once the > shared driver is in. Oh, I now took a closer look at the ssd16xx driver.  I thought that it would use the panel helpers, but that's not the case. It's a 'regular' DRM driver. If the ssd16xx does not make progress, we could also try to merge your code as ssd16xx and Devarsh would then add support for additional ICs on top. There's also the ssd130x driver under solomon/ how does it related to the ssd16xx? Is that similar as well? Best regards Thomas > > Devarsh, thank you again for sharing the branch, and for making room for > the panel in your work in the first place. I am glad to keep testing > SSD1677 on real hardware whenever that is useful to you. > > Regards, > LiangCheng -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com GF: Jochen Jaser, Andrew McDonald, (HRB 36809, AG Nürnberg)