From: Tom Gundersen <teg@jklm.no>
To: David Herrmann <dh.herrmann@gmail.com>
Cc: "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH v5 2/7] x86/sysfb: fix lfb_size calculation
Date: Fri, 2 Sep 2016 12:20:41 +0200 [thread overview]
Message-ID: <CAG-2HqViQ6a_520c=SCADFuO-j6p_OewkbOME_x40WkkWfjm3A@mail.gmail.com> (raw)
In-Reply-To: <20160902082245.7119-3-dh.herrmann@gmail.com>
On Fri, Sep 2, 2016 at 10:22 AM, David Herrmann <dh.herrmann@gmail.com> wrote:
> The screen_info.lfb_size field is shifted by 16 bits *only* in case of
> VBE. This has historical reasons since VBE advertised it similarly.
> However, in case of EFI framebuffers, the size is no longer shifted. Fix
> the x86 simple-framebuffer setup code to use the correct size in the
> non-VBE case.
>
> While at it, avoid variable abbreviations and rename 'len' to 'length',
> and use the correct types matching the screen_info definition.
>
> Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Tom Gundersen <teg@jklm.no>
> ---
> arch/x86/kernel/sysfb_simplefb.c | 25 +++++++++++++++++--------
> 1 file changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/kernel/sysfb_simplefb.c b/arch/x86/kernel/sysfb_simplefb.c
> index 35b8641..85195d4 100644
> --- a/arch/x86/kernel/sysfb_simplefb.c
> +++ b/arch/x86/kernel/sysfb_simplefb.c
> @@ -66,8 +66,8 @@ __init int create_simplefb(const struct screen_info *si,
> {
> struct platform_device *pd;
> struct resource res;
> - unsigned long len;
> - u64 base;
> + u64 base, size;
> + u32 length;
>
> /*
> * If the 64BIT_BASE capability is set, ext_lfb_base will contain the
> @@ -82,11 +82,20 @@ __init int create_simplefb(const struct screen_info *si,
> return -EINVAL;
> }
>
> - /* don't use lfb_size as it may contain the whole VMEM instead of only
> - * the part that is occupied by the framebuffer */
> - len = mode->height * mode->stride;
> - len = PAGE_ALIGN(len);
> - if (len > (u64)si->lfb_size << 16) {
> + /*
> + * Don't use lfb_size as IORESOURCE size, since it may contain the
> + * entire VMEM, and thus require huge mappings. Use just the part we
> + * need, that is, the part where the framebuffer is located. But verify
> + * that it does not exceed the advertised VMEM.
> + * Note that in case of VBE, the lfb_size is shifted by 16 bits for
> + * historical reasons.
> + */
> + size = si->lfb_size;
> + if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
> + size <<= 16;
> + length = mode->height * mode->stride;
> + length = PAGE_ALIGN(length);
> + if (length > size) {
> printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
> return -EINVAL;
> }
> @@ -96,7 +105,7 @@ __init int create_simplefb(const struct screen_info *si,
> res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> res.name = simplefb_resname;
> res.start = base;
> - res.end = res.start + len - 1;
> + res.end = res.start + length - 1;
> if (res.end <= res.start)
> return -EINVAL;
>
> --
> 2.9.3
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2016-09-02 10:21 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-02 8:22 [PATCH v5 0/7] drm: add simpledrm driver David Herrmann
2016-09-02 8:22 ` [PATCH v5 1/7] x86/sysfb: add support for 64bit EFI lfb_base David Herrmann
2016-09-02 10:20 ` Tom Gundersen
2016-09-02 8:22 ` [PATCH v5 2/7] x86/sysfb: fix lfb_size calculation David Herrmann
2016-09-02 10:20 ` Tom Gundersen [this message]
2016-09-02 8:22 ` [PATCH v5 3/7] of/platform: expose of_platform_device_destroy() David Herrmann
2016-09-02 10:21 ` Tom Gundersen
2016-09-02 8:22 ` [PATCH v5 4/7] video: add generic framebuffer eviction David Herrmann
2016-09-02 10:21 ` Tom Gundersen
2016-09-03 12:06 ` Noralf Trønnes
2016-09-05 11:19 ` David Herrmann
2016-09-05 16:36 ` Noralf Trønnes
2016-09-02 8:22 ` [PATCH v5 5/7] drm: switch to sysfb_evict_conflicts() David Herrmann
2016-09-03 12:13 ` Noralf Trønnes
2016-09-02 8:22 ` [PATCH v5 6/7] drm: add SimpleDRM driver David Herrmann
2016-09-02 12:45 ` Tom Gundersen
2016-09-03 12:01 ` Noralf Trønnes
2016-09-03 12:05 ` David Herrmann
2016-09-05 16:39 ` Noralf Trønnes
2016-09-02 8:22 ` [PATCH v5 7/7] drm/simpledrm: add fbdev fallback support David Herrmann
2016-09-03 12:04 ` Noralf Trønnes
2016-09-03 17:15 ` Noralf Trønnes
2016-09-05 11:21 ` David Herrmann
2021-03-10 2:50 ` [PATCH v5 0/7] drm: add simpledrm driver nerdopolis
2021-03-10 9:10 ` Thomas Zimmermann
2021-03-10 13:52 ` nerdopolis
2021-03-12 3:49 ` nerdopolis
2021-03-12 8:03 ` Thomas Zimmermann
2021-03-12 13:25 ` nerdopolis
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAG-2HqViQ6a_520c=SCADFuO-j6p_OewkbOME_x40WkkWfjm3A@mail.gmail.com' \
--to=teg@jklm.no \
--cc=dh.herrmann@gmail.com \
--cc=dri-devel@lists.freedesktop.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).