Re: [PATCH] i386/linux: add support for ext_lfb_base

[Daniel Kiper]

On Fri, Jun 29, 2018 at 12:18:29PM +0000, Nath, Arindam wrote:
> > -----Original Message-----
> > From: Arindam Nath <address@hidden> On Behalf Of Arindam Nath
> > Sent: Wednesday, June 27, 2018 8:26 PM
> > To: address@hidden
> > Cc: Nath, Arindam <address@hidden>
> > Subject: [PATCH] i386/linux: add support for ext_lfb_base
> >
> > The EFI Graphics Output Protocol can return a 64-bit
> > linear frame buffer address in some firmware/BIOS
> > implementations. We currently only store the lower
> > 32-bits in the lfb_base. This will eventually be
> > passed to Linux kernel and the efifb driver will
> > incorrectly interpret the framebuffer address as
> > 32-bit address.
> >
> > The Linux kernel has already added support to handle
> > 64-bit linear framebuffer address in the efifb driver
> > since quite some time now.
> >
> > This patch adds the support for 64-bit linear frame
> > buffer address in GRUB to address the above mentioned
> > scenario.
> >
> > Signed-off-by: Arindam Nath <address@hidden>
> > ---
> >  grub-core/loader/i386/linux.c | 2 ++
> >  include/grub/i386/linux.h     | 5 ++++-
> >  2 files changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/grub-core/loader/i386/linux.c b/grub-core/loader/i386/linux.c
> > index 083f9417c..1644e8132 100644
> > --- a/grub-core/loader/i386/linux.c
> > +++ b/grub-core/loader/i386/linux.c
> > @@ -306,6 +306,8 @@ grub_linux_setup_video (struct linux_kernel_params
> > *params)
> >    params->lfb_line_len = mode_info.pitch;
> >
> >    params->lfb_base = (grub_size_t) framebuffer;
> > +  params->ext_lfb_base = (grub_size_t) (((grub_uint64_t)(grub_size_t)
> > framebuffer) >> 32);
> > +  params->capabilities |= VIDEO_CAPABILITY_64BIT_BASE;
> >    params->lfb_size = ALIGN_UP (params->lfb_line_len * params->lfb_height,
> > 65536);
> >
> >    params->red_mask_size = mode_info.red_mask_size;
> > diff --git a/include/grub/i386/linux.h b/include/grub/i386/linux.h
> > index da0ca3b83..e3f91e7c0 100644
> > --- a/include/grub/i386/linux.h
> > +++ b/include/grub/i386/linux.h
> > @@ -188,8 +188,11 @@ struct linux_kernel_params
> >    grub_uint16_t lfb_pages;         /* 32 */
> >    grub_uint16_t vesa_attrib;               /* 34 */
> >    grub_uint32_t capabilities;              /* 36 */
> > +#define VIDEO_CAPABILITY_SKIP_QUIRKS       (1 << 0)
> > +#define VIDEO_CAPABILITY_64BIT_BASE        (1 << 1)        /* Frame buffer 
> > base
> > is 64-bit */
> > +  grub_uint32_t ext_lfb_base;              /* 3a */
> >
> > -  grub_uint8_t padding3[0x40 - 0x3a];
> > +  grub_uint8_t padding3[0x40 - 0x3e];
> >
> >    grub_uint16_t apm_version;               /* 40 */
> >    grub_uint16_t apm_code_segment;  /* 42 */
> > --
> > 2.17.1
>
> Could you help review the changes?

I have just come back from the vacation. So, I will take a look
at this probably this week after clearing my backlog.

By the way, please remember that the reviewers are also busy with
other stuff and they may not be able to review the patches on day
to day basis. So, please give them a week or two to do that. If this
does not happen in that timeframe then just bump the thread but
not earlier please.

Daniel