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Message-ID: <9c22b709-cbcf-6a29-a45e-5a57ba0b9c14@gmx.de>
Date:   Tue, 1 Feb 2022 11:16:04 +0100
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Subject: Re: [PATCH 03/21] fbcon: Restore fbcon scrolling acceleration
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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>
From:   Helge Deller <deller@gmx.de>
In-Reply-To: <20220131210552.482606-4-daniel.vetter@ffwll.ch>
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Precedence: bulk

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 prevent=
 the
console acceleration.

> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core=
/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 i=
nit)
>
>  	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_displa=
y *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


> +	p->scrollmode =3D SCROLL_REDRAW;
> +#endif
>  }
>
>  #define PITCH(w) (((w) + 7) >> 3)
>

still reviewing the other patches...

Helge