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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
	syzbot <syzbot+04168c8063cfdde1db5e@syzkaller.appspotmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Colin King <colin.king@canonical.com>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	Linux Fbdev development list <linux-fbdev@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	syzkaller-bugs@googlegroups.com,
	Randy Dunlap <rdunlap@infradead.org>
Subject: Re: [PATCH] fbmem: don't allow too huge resolutions
Date: Tue, 31 Aug 2021 19:19:27 +0200	[thread overview]
Message-ID: <CAMuHMdWbSUGRGAVi-17C3hyDBZnGLAsmbAs+wXPHiCNWWLbMpA@mail.gmail.com> (raw)
In-Reply-To: <5c6d2b95-31d7-0d59-5e62-2593d9a0e1fe@i-love.sakura.ne.jp>

Hi Handa-san,

On Tue, Aug 31, 2021 at 5:24 PM Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> 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.

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

  parent reply	other threads:[~2021-08-31 17:19 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-14  5:16 [syzbot] BUG: unable to handle kernel paging request in vga16fb_fillrect syzbot
2021-08-30  0:24 ` Randy Dunlap
2021-08-30  2:27   ` Tetsuo Handa
2021-08-30  2:31     ` Randy Dunlap
2021-08-30 16:05       ` [PATCH] fbmem: don't allow too huge resolutions Tetsuo Handa
2021-08-31  6:48         ` Geert Uytterhoeven
2021-08-31 15:23           ` Tetsuo Handa
2021-08-31 16:20             ` Daniel Vetter
2021-08-31 17:19             ` Geert Uytterhoeven [this message]
2021-08-31 18:53               ` Daniel Vetter
2021-08-31 18:56                 ` Geert Uytterhoeven
2021-08-31 19:04                   ` Daniel Vetter
2021-09-01  1:14                     ` [PATCH v2] " Tetsuo Handa
2021-09-01  7:12                       ` Geert Uytterhoeven
2021-09-08 10:27                       ` [PATCH v2 (repost)] " Tetsuo Handa
2021-09-08 16:52                         ` Daniel Vetter
2021-08-30 12:00     ` [syzbot] BUG: unable to handle kernel paging request in vga16fb_fillrect Geert Uytterhoeven
2021-08-30 13:00       ` Dan Carpenter
2021-08-30 13:37         ` Tetsuo Handa
2021-08-30 13:47           ` Dan Carpenter
2021-08-30 14:25             ` Tetsuo Handa
2021-08-30 14:29               ` Dan Carpenter
2021-08-30 14:30               ` Geert Uytterhoeven
2021-08-30 14:38                 ` Tetsuo Handa
2021-08-30 14:53                   ` Geert Uytterhoeven
2021-08-30 15:00                     ` Geert Uytterhoeven

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