From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51574C432BE for ; Tue, 31 Aug 2021 18:56:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 230E061056 for ; Tue, 31 Aug 2021 18:56:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236193AbhHaS5f (ORCPT ); Tue, 31 Aug 2021 14:57:35 -0400 Received: from mail-vs1-f53.google.com ([209.85.217.53]:36407 "EHLO mail-vs1-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231514AbhHaS5f (ORCPT ); Tue, 31 Aug 2021 14:57:35 -0400 Received: by mail-vs1-f53.google.com with SMTP id f6so402275vsr.3; Tue, 31 Aug 2021 11:56:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=0hrVR/Pp4bY5ExwU3CuX6SzlhALUUdWlYKXEp50Y348=; b=E4t68AklQrX2lq5RL1ENJVvNyuhvJtS3PzlCMQi1hXmCI74aBIeGTykQ1GvAjoct6w d7I+w6aADQDe7brIe8p8WvFC6YqEsisd3Kwm4zcddOQBIMYCE3E2Kvd3cUftYOrCS0kl LNOvN0r+65222zmakGtqzUtXBRSdAbShWYOJzC6E/Xzs2WQGjKPaPL1QkJJ7C4Kv+LUg zoZqb6Z/URehsv6iW9XItS/VH17h/u5pl8S9YugnA7afDjawhDLtr+hv+ex/5ZtFYCoS z+MXIbtPgeaJPAg6p7Dme7Ijc2b2lwAzGgaPZi3zJNLaBT44BkoxBG4fh/Sa1xs+6zs8 aoYw== X-Gm-Message-State: AOAM532nGSK0wbQZKkgVM7YQd8aBWQYpfeTTuLgC4Geomc/OCETYNkv+ FyB+el6R+N5qDRHES+NnxAy64PwsB8JVV7x3S77cH6VU X-Google-Smtp-Source: ABdhPJz9v59KKZoqK9rLnaHapES3XW5DBPdu8VPOELGOeHWSav0EGFF40rmu9oSffgZtAtzQvdPp23duhz+ykWeWZKU= X-Received: by 2002:a67:cb0a:: with SMTP id b10mr20702000vsl.9.1630436198992; Tue, 31 Aug 2021 11:56:38 -0700 (PDT) MIME-Version: 1.0 References: <000000000000815b9605c70e74f8@google.com> <131b24e5-ee31-6f7b-42b4-c34583711913@infradead.org> <2fccb5d3-191c-924e-159f-1c9d423e282f@i-love.sakura.ne.jp> <339bfb21-8e80-c7d9-46dd-c416f87c50c0@infradead.org> <535e404d-03bf-8e7a-b296-132a2a98c599@i-love.sakura.ne.jp> <5c6d2b95-31d7-0d59-5e62-2593d9a0e1fe@i-love.sakura.ne.jp> In-Reply-To: From: Geert Uytterhoeven Date: Tue, 31 Aug 2021 20:56:27 +0200 Message-ID: Subject: Re: [PATCH] fbmem: don't allow too huge resolutions To: Daniel Vetter Cc: Tetsuo Handa , syzbot , Andrew Morton , Bartlomiej Zolnierkiewicz , Colin King , DRI Development , Linux Fbdev development list , Linux Kernel Mailing List , Masahiro Yamada , syzkaller-bugs , Randy Dunlap Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org Hi Daniel, On Tue, Aug 31, 2021 at 8:53 PM Daniel Vetter wrote: > On Tue, Aug 31, 2021 at 7:19 PM Geert Uytterhoeven wrote: > > On Tue, Aug 31, 2021 at 5:24 PM Tetsuo Handa > > wrote: > > > On 2021/08/31 15:48, Geert Uytterhoeven wrote: > > > > Furthermore, this restricts the virtual frame buffer size on 64-bit, > > > > too, while graphics cards can have much more than 4 GiB of RAM. > > > > > > Excuse me, but do you mean that some hardware allows allocating more than > > > UINT_MAX bytes of memory for kernel frame buffer drivers? > > > > While smem_len is u32 (there have been complaints about such > > limitations on 64-bit platforms as far as 10 years ago), I see no > > reason why a graphics card with more than 4 GiB of RAM would not be > > able to provide a very large virtual screen. > > > > Of course e.g. vga16fb cannot, as it is limited to 64 KiB. > > The first gpus with 4GB or more memory started shipping in 2012. We're > not going to have fbdev drivers for these, so let's not invent code > for use-cases that aren't please. This code path is used with fbdev emulation for drm drivers, too, right? 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