From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geert Uytterhoeven Date: Fri, 23 Sep 2011 05:17:03 +0000 Subject: Re: [PATCH] gma500: gtt based hardware scrolling console Message-Id: List-Id: References: <20110922184316.25068.54702.stgit@localhost.localdomain> <20110922212146.609065b1@lxorguk.ukuu.org.uk> In-Reply-To: <20110922212146.609065b1@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: Alan Cox Cc: greg@kroah.com, linux-kernel@vger.kernel.org, Linux Fbdev development list On Thu, Sep 22, 2011 at 22:21, Alan Cox wrote: >> > +       info->fix.ywrapstep = gtt_roll; >> >> Do you really want to set this? I didn't see any other wrapping >> support in your patch. >> However, I guess you can implement wrapping support using the same >> mapping trick? > > It is actually wrapping - it writes the low pages back below the high > ones so it works the GTT as a circular buffer - or am I misunderstanding > this. Then it should not set ypanstep to a non-zero value, and set/handle the other various *YWRAP flags, to communicate with the frame buffer console driver. Panning is moving inside a virtual screen bigger than the visible screen size. > One thing I wasn't sure of on the fb side. If I've got a display width > that is annoying and can't fit on a 4Kbyte stride am I right in thinking > I can set this to say 8 and use a 512 byte stride and still get > acceleration for the usual font choice ? Yep, that should work. The console code can use ywrap resp. ypan if the font height is a multiple of ywrapstep resp. ypanstep. Gr{oetje,eeting}s,                         Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that.                                 -- Linus Torvalds