Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <98bf57d3-de0f-7f0e-21ce-360f661f4e25@gmx.de>
Date:   Tue, 1 Feb 2022 11:17:44 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.3.0
Subject: Re: [PATCH 03/21] fbcon: Restore fbcon scrolling acceleration
Content-Language: en-US
From:   Helge Deller <deller@gmx.de>
To:     Daniel Vetter <daniel.vetter@ffwll.ch>,
        DRI Development <dri-devel@lists.freedesktop.org>
Cc:     Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
        linux-fbdev@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        stable@vger.kernel.org, Claudio Suarez <cssk@net-c.es>,
        Dave Airlie <airlied@gmail.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Pavel Machek <pavel@ucw.cz>, Sam Ravnborg <sam@ravnborg.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Javier Martinez Canillas <javierm@redhat.com>,
        Tomi Valkeinen <tomi.valkeinen@ti.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Daniel Vetter <daniel.vetter@intel.com>,
        Sven Schnelle <svens@stackframe.org>,
        Gerd Hoffmann <kraxel@redhat.com>
References: <20220131210552.482606-1-daniel.vetter@ffwll.ch>
 <20220131210552.482606-4-daniel.vetter@ffwll.ch>
 <9c22b709-cbcf-6a29-a45e-5a57ba0b9c14@gmx.de>
In-Reply-To: <9c22b709-cbcf-6a29-a45e-5a57ba0b9c14@gmx.de>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On 2/1/22 11:16, Helge Deller wrote:
> On 1/31/22 22:05, Daniel Vetter wrote:
>> This functionally undoes 39aead8373b3 ("fbcon: Disable accelerated
>> scrolling"), but behind the FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION
>> option.
>
> you have two trivial copy-n-paste errors in this patch which still preve=
nt the
> console acceleration.
>
>> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/cor=
e/fbcon.c
>> index 2ff90061c7f3..39dc18a5de86 100644
>> --- a/drivers/video/fbdev/core/fbcon.c
>> +++ b/drivers/video/fbdev/core/fbcon.c
>> @@ -1125,13 +1125,15 @@ static void fbcon_init(struct vc_data *vc, int =
init)
>>
>>  	ops->graphics =3D 0;
>>
>> -	/*
>> -	 * No more hw acceleration for fbcon.
>> -	 *
>> -	 * FIXME: Garbage collect all the now dead code after sufficient time
>> -	 * has passed.
>> -	 */
>> +#ifdef CONFIG_FRAMEBUFFER_CONSOLE_ROTATION
>
> should be:
> #ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION
>
>
>> +	if ((info->flags & FBINFO_HWACCEL_COPYAREA) &&
>> +	    !(info->flags & FBINFO_HWACCEL_DISABLED))
>> +		p->scrollmode =3D SCROLL_MOVE;
>> +	else /* default to something safe */
>> +		p->scrollmode =3D SCROLL_REDRAW;
>> +#else
>>  	p->scrollmode =3D SCROLL_REDRAW;
>> +#endif
>>
>>  	/*
>>  	 *  ++guenther: console.c:vc_allocate() relies on initializing
>> @@ -1971,15 +1973,49 @@ static void updatescrollmode(struct fbcon_displ=
ay *p,
>>  {
>>  	struct fbcon_ops *ops =3D info->fbcon_par;
>>  	int fh =3D vc->vc_font.height;
>> +	int cap =3D info->flags;
>> +	u16 t =3D 0;
>> +	int ypan =3D FBCON_SWAP(ops->rotate, info->fix.ypanstep,
>> +			      info->fix.xpanstep);
>> +	int ywrap =3D FBCON_SWAP(ops->rotate, info->fix.ywrapstep, t);
>>  	int yres =3D FBCON_SWAP(ops->rotate, info->var.yres, info->var.xres);
>>  	int vyres =3D FBCON_SWAP(ops->rotate, info->var.yres_virtual,
>>  				   info->var.xres_virtual);
>> +	int good_pan =3D (cap & FBINFO_HWACCEL_YPAN) &&
>> +		divides(ypan, vc->vc_font.height) && vyres > yres;
>> +	int good_wrap =3D (cap & FBINFO_HWACCEL_YWRAP) &&
>> +		divides(ywrap, vc->vc_font.height) &&
>> +		divides(vc->vc_font.height, vyres) &&
>> +		divides(vc->vc_font.height, yres);
>> +	int reading_fast =3D cap & FBINFO_READS_FAST;
>> +	int fast_copyarea =3D (cap & FBINFO_HWACCEL_COPYAREA) &&
>> +		!(cap & FBINFO_HWACCEL_DISABLED);
>> +	int fast_imageblit =3D (cap & FBINFO_HWACCEL_IMAGEBLIT) &&
>> +		!(cap & FBINFO_HWACCEL_DISABLED);
>>
>>  	p->vrows =3D vyres/fh;
>>  	if (yres > (fh * (vc->vc_rows + 1)))
>>  		p->vrows -=3D (yres - (fh * vc->vc_rows)) / fh;
>>  	if ((yres % fh) && (vyres % fh < yres % fh))
>>  		p->vrows--;
>> +
>> +	if (good_wrap || good_pan) {
>> +		if (reading_fast || fast_copyarea)
>> +			p->scrollmode =3D good_wrap ?
>> +				SCROLL_WRAP_MOVE : SCROLL_PAN_MOVE;
>> +		else
>> +			p->scrollmode =3D good_wrap ? SCROLL_REDRAW :
>> +				SCROLL_PAN_REDRAW;
>> +	} else {
>> +		if (reading_fast || (fast_copyarea && !fast_imageblit))
>> +			p->scrollmode =3D SCROLL_MOVE;
>> +		else
>> +			p->scrollmode =3D SCROLL_REDRAW;
>> +	}
>> +
>> +#ifndef CONFIG_FRAMEBUFFER_CONSOLE_ROTATION
>
> same here... it needs to be:
> #ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION

actually:
#ifndef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION

>
>
>> +	p->scrollmode =3D SCROLL_REDRAW;
>> +#endif
>>  }
>>
>>  #define PITCH(w) (((w) + 7) >> 3)
>>
>
> still reviewing the other patches...
>
> Helge
>