From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 986F02DCF61 for ; Mon, 8 Dec 2025 08:30:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765182604; cv=none; b=RM7Hu63e65DLWfLji1W2qwtE/4YgDlXy3J0KNNhAZbD3MO6r8vl2dM79aCfUo1ZyPqhl8HesqWTVE6wDvJ50tlz2MRibMOKoIqzjlMgRRZCRjan91WAn6o/7qjL0aGDyVcXkRTWrhCvc5bmOVv8cEI7SZdOcxHIlt4wpZvImmvU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765182604; c=relaxed/simple; bh=O343ejqumZnJZz1NubjqOVL5Uy/d/TZDIO6H2W6/UHY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=RB3jEKzE4Fv28yar2ztMDV1hTsEDPA0R8u5pcfrsntjPsO/JmMsFFC+ndpyjQFK7pWfJIk32m/ZyBRZ1+2Cn+LKsgCehpZfJpDs1zFbjhLwHWjt5vdhlPF/TK8HQQXyjGlFPAEeqlu7biCUfKyeMuRk6toMjiKyG8fABRPkw3M4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de; spf=pass smtp.mailfrom=suse.de; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=sd4PnFVt; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=BgRPLTt5; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=sd4PnFVt; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=BgRPLTt5; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="sd4PnFVt"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="BgRPLTt5"; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="sd4PnFVt"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="BgRPLTt5" Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 0BDD933849; Mon, 8 Dec 2025 08:29:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1765182594; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=txAEDolAm+qx9EKDUzNM1Dzpyph1t3vIgVGEU6Q1+bg=; b=sd4PnFVtjLoipHwrQInn64sDZyCc3Rx32hdJ9VaMnz1oIHO3QM6Hr2IoydCH6upI/th/gm IasXaHUB+EqlGhGu4HazbnhTJGAbSiw0Mr0609TTw/aBeGDXm9fbpk3CXFypjUHbsWjU6w 96Ps+j7JSmD0VhMtSS7JQZMzluaeJpQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1765182594; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=txAEDolAm+qx9EKDUzNM1Dzpyph1t3vIgVGEU6Q1+bg=; b=BgRPLTt5tAppddr9Yy16j3m4n10KFPluLp0pR+govG6emQPsGUXWzvyz9mjGE/SHVrYdR8 8YPKHKXuemnl/+Cw== Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=sd4PnFVt; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=BgRPLTt5 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1765182594; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=txAEDolAm+qx9EKDUzNM1Dzpyph1t3vIgVGEU6Q1+bg=; b=sd4PnFVtjLoipHwrQInn64sDZyCc3Rx32hdJ9VaMnz1oIHO3QM6Hr2IoydCH6upI/th/gm IasXaHUB+EqlGhGu4HazbnhTJGAbSiw0Mr0609TTw/aBeGDXm9fbpk3CXFypjUHbsWjU6w 96Ps+j7JSmD0VhMtSS7JQZMzluaeJpQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1765182594; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=txAEDolAm+qx9EKDUzNM1Dzpyph1t3vIgVGEU6Q1+bg=; b=BgRPLTt5tAppddr9Yy16j3m4n10KFPluLp0pR+govG6emQPsGUXWzvyz9mjGE/SHVrYdR8 8YPKHKXuemnl/+Cw== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id D9D3D3EA63; Mon, 8 Dec 2025 08:29:53 +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 24FbMYGMNmnrXwAAD6G6ig (envelope-from ); Mon, 08 Dec 2025 08:29:53 +0000 Message-ID: <816e40d2-e451-4d70-bc44-e07562138b1b@suse.de> Date: Mon, 8 Dec 2025 09:29:53 +0100 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 V2] drm/mgag200: Fix big-endian support To: =?UTF-8?Q?Ren=C3=A9_Rebe?= , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: Dave Airlie References: <20251205.182405.876575799174263183.rene@exactco.de> 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: <20251205.182405.876575799174263183.rene@exactco.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Flag: NO X-Spam-Score: -4.51 X-Rspamd-Queue-Id: 0BDD933849 X-Spamd-Result: default: False [-4.51 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; MID_RHS_MATCH_FROM(0.00)[]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; MIME_TRACE(0.00)[0:+]; TO_DN_SOME(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FUZZY_RATELIMITED(0.00)[rspamd.com]; ARC_NA(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim,suse.de:mid,bootlin.com:url,imap1.dmz-prg2.suse.org:rdns,imap1.dmz-prg2.suse.org:helo,exactco.de:email,suse.com:url]; DNSWL_BLOCKED(0.00)[2a07:de40:b281:106:10:150:64:167:received]; TO_MATCH_ENVRCPT_ALL(0.00)[]; URIBL_BLOCKED(0.00)[imap1.dmz-prg2.suse.org:rdns,imap1.dmz-prg2.suse.org:helo,suse.com:url,bootlin.com:url,suse.de:dkim,suse.de:mid]; DKIM_TRACE(0.00)[suse.de:+] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Action: no action X-Spam-Level: Hi, thanks for the update. Am 05.12.25 um 18:24 schrieb René Rebe: > Unlike the original, deleted Matrox mga driver, the new mgag200 driver > has the XRGB frame-buffer byte swapped on big-endian "RISC" > systems. Fix by enabling byte swapping "PowerPC" OPMODE for any > __BIG_ENDIAN config. > > Fixes: 414c45310625 ("mgag200: initial g200se driver (v2)") > Signed-off-by: René Rebe > Cc: stable@kernel.org > --- > V2: move to atomic_update > Tested on IBM 43p Model 150 (7043-150) running T2/Linux. > --- > drivers/gpu/drm/mgag200/mgag200_mode.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c > index 951d715dea30..d40434ec68ab 100644 > --- a/drivers/gpu/drm/mgag200/mgag200_mode.c > +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c > @@ -496,6 +496,20 @@ void mgag200_primary_plane_helper_atomic_update(struct drm_plane *plane, > struct drm_atomic_helper_damage_iter iter; > struct drm_rect damage; > > +#ifdef __BIG_ENDIAN > + /* Big-endian byte-swapping */ > + switch (fb->format->format) { > + case DRM_FORMAT_RGB565: > + WREG32(MGAREG_OPMODE, 0x10100); > + break; > + case DRM_FORMAT_XRGB8888: > + WREG32(MGAREG_OPMODE, 0x20200); > + break; > + default: > + break; No need for a default branch IIRC. > + } This is the right place to set up the write mode. But looking at the G200 docs, I found that the reset value for OPMODE has bit 18 set to 1. These writes clear the value. If that intentional? For better style and compatibility, I suggest to first read the value and keep the reserved bit as-is. u32 opmode opmode = RREG32(MGAREG_OPMODE) opmode &= ~GENMASK(17, 16) opmode &= ~GENMASK(9, 8) opmode &= ~GENMASK(3, 2) switch (format) {         opmode |= ...; } WREG32(OPMODE, opmode); You can put that in a helper near set_startadd [1] void mgag200_set_datasiz(struct mga_device *mdev, u32 format) { #if __BIG_ENDIAN ... #endif } Then call that from atomic_update and it should be fine. [1] https://elixir.bootlin.com/linux/v6.18/source/drivers/gpu/drm/mgag200/mgag200_mode.c#L117 Best regards Thomas > +#endif > + > drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state); > drm_atomic_for_each_plane_damage(&iter, &damage) { > mgag200_handle_damage(mdev, shadow_plane_state->data, fb, &damage); -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)