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 EA07B1487C3; Fri, 14 Jun 2024 07:24:07 +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=1718349849; cv=none; b=GU0jL6nWR/+5N2+/YiiZLsIZjp3wUvB9TNGA8/1moiw+JKxLxie/48WTFh9axUNdSScMyXquWtRDlPNEyv+swl9d5uYIIo7P8bDvm0EAUOaSCjl0thjNJIL2GYtJ9U9GJ4+A112KqfO1jaQeP0Bjp1TDRaV/NEqZYoKvaxhv+3I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718349849; c=relaxed/simple; bh=g+9kGhRKZClOIfInNoKZHAFjPZZSJyHarCLa1hSe3vY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=r9m6C+OrGu73mVsV/ss6YpeSbTgcuqpQ22YjiL5EG25ZIS93+ihxevScemzOTMkAbHaDEpC1qUIPZBYJem316Qcc89z/fdtffk05ok1BU6GzYcUDwwoiLWy5xgkF90InxvYOJ5ISPyF4wntCLfpqcB1ZSOjnhb4S243VtHrqdGg= 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=l6qk5MK/; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=OsgcPN0G; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=lfLDkCeX; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=w8ER1qIE; 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="l6qk5MK/"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="OsgcPN0G"; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="lfLDkCeX"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="w8ER1qIE" 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 DE059221E5; Fri, 14 Jun 2024 07:23:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1718349840; 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=2b0mkGYWVL8dqww12f5KC+N567kXNMjRf3DIoJnRcV0=; b=l6qk5MK/tY3vBuO9i2B32BU+qzv63hTXHkOPedjflp5JpbsJWqSZC+9rlYCtUVHMTxJRVS NaaPQ7yCNiN0Lx4qWK+nQ3ndPQDyF5Tn0f77ohbYAeAgE5inLjjeJYzwMiM95ZkttprsFF n0iOgjFQ7pM43gYgmchuE4WN120cWP8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1718349840; 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=2b0mkGYWVL8dqww12f5KC+N567kXNMjRf3DIoJnRcV0=; b=OsgcPN0GZgtRAMXY8vWgiV42wE5qflifRw9mzR4/cs5A00Tw8tQEWDTsqIMt3JrFOJxhNV FCcEZuoAsxfPPaDQ== Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=lfLDkCeX; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=w8ER1qIE DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1718349839; 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=2b0mkGYWVL8dqww12f5KC+N567kXNMjRf3DIoJnRcV0=; b=lfLDkCeXCqwn+8LqKmQUWOlhDh0QfAMP9P2krzdBdkeY4TUmXGSJ2d+5uC22hhwdTX1a+S NJ+dmvzSiO7omKN+5+lPzqmrr2VZr1rBIJo5uInKHQGJ8vUsIzk2dQosOZBG1qYS2cZpS6 crUX2dD95pOnpUUUqCN9HmcsyL1KEbU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1718349839; 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=2b0mkGYWVL8dqww12f5KC+N567kXNMjRf3DIoJnRcV0=; b=w8ER1qIEdN+bEVgMOrSssGX4edeHxjUACQmu1GuLGHpj/ojQOD1+6kRB7rFr0/CajJuwyK K9KzfE/5xS30JmCg== 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 9E1C613AAF; Fri, 14 Jun 2024 07:23:59 +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 2JD6JA/wa2b8UAAAD6G6ig (envelope-from ); Fri, 14 Jun 2024 07:23:59 +0000 Message-ID: <9f2e4bc5-fa0a-4910-85d0-c76559a5ae37@suse.de> Date: Fri, 14 Jun 2024 09:23:59 +0200 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] fbdev: vesafb: Detect VGA compatibility from screen info's VESA attributes To: Helge Deller , Javier Martinez Canillas , sam@ravnborg.org, hpa@zytor.com Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, stable@vger.kernel.org References: <20240613090240.7107-1-tzimmermann@suse.de> <5d8d2efe-45dd-4033-aaae-e7f923ef9e76@gmx.de> <87tthwqzq2.fsf@minerva.mail-host-address-is-not-set> <64bbb753-ec26-41ca-a585-fb74ae9e854c@gmx.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: <64bbb753-ec26-41ca-a585-fb74ae9e854c@gmx.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: DE059221E5 X-Spam-Score: -6.50 X-Spam-Level: X-Spam-Flag: NO X-Spamd-Result: default: False [-6.50 / 50.00]; BAYES_HAM(-3.00)[100.00%]; DWL_DNSWL_MED(-2.00)[suse.de:dkim]; 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)[-1.000]; MIME_GOOD(-0.10)[text/plain]; XM_UA_NO_VERSION(0.01)[]; MX_GOOD(-0.01)[]; FREEMAIL_TO(0.00)[gmx.de,redhat.com,ravnborg.org,zytor.com]; TO_DN_SOME(0.00)[]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FUZZY_BLOCKED(0.00)[rspamd.com]; MIME_TRACE(0.00)[0:+]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FREEMAIL_ENVRCPT(0.00)[gmx.de]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; RCVD_COUNT_TWO(0.00)[2]; MID_RHS_MATCH_FROM(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCPT_COUNT_SEVEN(0.00)[7]; RCVD_VIA_SMTP_AUTH(0.00)[]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; RCVD_TLS_ALL(0.00)[]; DKIM_TRACE(0.00)[suse.de:+]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns,suse.de:email,suse.de:dkim,gmx.de:email] X-Rspamd-Action: no action X-Rspamd-Server: rspamd1.dmz-prg2.suse.org Hi Am 14.06.24 um 00:24 schrieb Helge Deller: > On 6/13/24 23:50, Javier Martinez Canillas wrote: >> Helge Deller writes: >> >>> On 6/13/24 11:02, Thomas Zimmermann wrote: >>>> Test the vesa_attributes field in struct screen_info for compatibility >>>> with VGA hardware. Vesafb currently tests bit 1 in screen_info's >>>> capabilities field, It sets the framebuffer address size and is >>>> unrelated to VGA. >>>> >>>> Section 4.4 of the Vesa VBE 2.0 specifications defines that bit 5 in >>>> the mode's attributes field signals VGA compatibility. The mode is >>>> compatible with VGA hardware if the bit is clear. In that case, the >>>> driver can access VGA state of the VBE's underlying hardware. The >>>> vesafb driver uses this feature to program the color LUT in palette >>>> modes. Without, colors might be incorrect. >>>> >>>> The problem got introduced in commit 89ec4c238e7a ("[PATCH] vesafb: >>>> Fix >>>> incorrect logo colors in x86_64"). It incorrectly stores the mode >>>> attributes in the screen_info's capabilities field and updates vesafb >>>> accordingly. Later, commit 5e8ddcbe8692 ("Video mode probing >>>> support for >>>> the new x86 setup code") fixed the screen_info, but did not update >>>> vesafb. >>>> Color output still tends to work, because bit 1 in capabilities is >>>> usually 0. >>>> >>>> Besides fixing the bug in vesafb, this commit introduces a helper that >>>> reads the correct bit from screen_info. >>> >>> Nice catch, Thomas! >>> >>> But do we really need this additional helper? Yes, please. Decoding screen_info is a science on it's own. I've added several of these helpers to access because such code was open-coded and duplicated all over the graphics code. And several places got something wrong. The patch here is just one of many such cases. >>> >>> >>>> >>>> Signed-off-by: Thomas Zimmermann >>>> Fixes: 5e8ddcbe8692 ("Video mode probing support for the new x86 >>>> setup code") >>>> Cc: # v2.6.23+ >>> >>>> --- >>>>    drivers/video/fbdev/vesafb.c | 2 +- >>>>    include/linux/screen_info.h  | 5 +++++ >>>>    2 files changed, 6 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/video/fbdev/vesafb.c >>>> b/drivers/video/fbdev/vesafb.c >>>> index 8ab64ae4cad3e..5a161750a3aee 100644 >>>> --- a/drivers/video/fbdev/vesafb.c >>>> +++ b/drivers/video/fbdev/vesafb.c >>>> @@ -271,7 +271,7 @@ static int vesafb_probe(struct platform_device >>>> *dev) >>>>        if (si->orig_video_isVGA != VIDEO_TYPE_VLFB) >>>>            return -ENODEV; >>>> >>>> -    vga_compat = (si->capabilities & 2) ? 0 : 1; >>>> +    vga_compat = !__screen_info_vbe_mode_nonvga(si); >>> >>> Instead maybe just this: ? >>>    +    /* mode is VGA-compatible if BIT 5 is _NOT_ set */ >>>    +    vga_compat = (si->vesa_attributes & BIT(5)) == 0; >>> >>> I suggest to make patch small, esp. if you ask for backport to >>> v2.6.23+. >>> >> >> I prefer the helper. It's a static inline anyways and having it as a >> function makes it much easier to read / understand. > > Really? Yep. > > +static inline bool __screen_info_vbe_mode_nonvga(const struct > screen_info *si) > +{ > +    return si->vesa_attributes & BIT(5); // VGA if _not_ set > +} > > At least the double negation "!nonvga()" breaks my head and the "//" > comment > should be converted to /*..*/ IMHO. The non-VGA bit is specified by VESA. So the helper does the correct thing. We can make a better comment though. If we want to simplify usage of this helper, I'd say we should kick vga_compat from vesafb and rework that code. Best regards Thomas > > Helge -- -- 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)