src/sys/dev/fb/vesa.c, branch stable/14

fb: Explicitly handle errors when getting or setting a colour palette

2024-01-04T13:42:13+00:00

In the VESA driver, simply ignore errors.  It is not clear to me how to
return them to userspace.

This is in preparation for annotating copyin() and related functions
with __result_use_check.

MFC after:	1 week

(cherry picked from commit ddc8576d297937a1395f47550a8f5b1fac79afc2)

sys: Remove $FreeBSD$: one-line .c pattern

2023-08-16T17:54:36+00:00

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

2023-05-12T16:44:03+00:00

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with:		pfg
MFC After:		3 days
Sponsored by:		Netflix

pmap_unmapdev/bios: Accept a pointer instead of a vm_offset_t.

2022-09-22T22:08:52+00:00

This matches the return type of pmap_mapdev/bios.

Reviewed by:	kib, markj
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D36548

Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many)

2020-02-26T14:26:36+00:00

r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.

This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.

Mark all obvious cases as MPSAFE.  All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT

Approved by:	kib (mentor, blanket)
Commented by:	kib, gallatin, melifaro
Differential Revision:	https://reviews.freebsd.org/D23718

Stop the VESA driver from whining loudly in the dmesg during boot on

2019-11-13T15:31:31+00:00

systems that use EFI instead of BIOS.

sys/dev: further adoption of SPDX licensing ID tags.

2017-11-27T14:52:40+00:00

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Write-combine framebuffer writes through user-space mappings, if possible.

2017-04-20T15:18:15+00:00

Note that KVA mapping of the framebuffer already uses write-combining
mode, so the change, besides improving speed of user mode writes, also
satisfies requirement of the IA32 architecture of using consistent
caching modes for multiple mappings of the same page.

Reported and tested by:	bde
Sponsored by:	The FreeBSD Foundation
MFC after:	 1 week

Attempt to determine the modes in which 8-bit wide characters are actually

2017-04-20T13:46:55+00:00

9 wide.

I only need this to improve the mouse cursor, but it has always been
needed to select and/or adjust fonts.

This is complicated because there are no standard parameter tables
giving this bit of information directly, and the device register bit
giving the information can't be trusted even if it is read from the
hardware.  Use a heuristic to guess if the device register can be
trusted.  (The device register is normally read from the BIOS mode
table, but on my system where the device register is wrong, the mode
table doesn't match the hardware and is not used; the device registers
are used in this case.)

Reset the DAC to 6-bit mode before calling the BIOS to set the screen

2017-04-02T08:39:32+00:00

mode.  This works around bugs in at least 2 Intel BIOSes for our
subsequent setting of the DAC back to 8-bit mode.  The bug caused dark
(mostly 1/4-intensity) colors for all except the first setting to a
VESA graphics mode (including for settings to the current mode).

Remove restoration (with less bits) of the palette in vesa_unload()
after resetting the DAC to 6-bit mode.  Depend on the BIOS to keep
the palette consistent with the DAC for the simpler reset case like
we do everywhere else in places that are actually important.

Setting the video mode should reset everything to defaults, although
we usually don't want that.  Even the buggy BIOSes set the DAC to the
default 6-bit mode, and set the palette to a default that matches the
DAC.  We don't undo the reset for most things, but we do undo it for
the DAC (more precisely, we change to an 8-bit DAC if possible, and
this is the only way that we set to an 8-bit DAC; it is accidental
that if the DAC was in 8-bit mode from a previous mode switch then
setting it to 8-bit mode is an undo).  The buggy BIOSes are confused
by our setting of the DAC to 8-bit mode in the "undo" case.  They
should multiply palette entries by 4 to match, but they actually leave
all palette entries except #2 (green) and #248-255 (unused) untouched.
Green is mysteriously scaled from 0x2a to 0x6a, and #248-255 are scaled
correctly.

Our support for the 8-bit DAC had almost no effect except to enable
bugs.  Syscons barely supports 16 colors, so it doesn't benefit much
from having a palette with 16 million colors instead of only 256K.
Applications can manage the palette using FBIO_{GET,SET}PALETTE, but
the palette managed by this is only used in the less interesting modes
(text and non-truecolor graphics modes up to 8 bits wide), and the
kernel loses the changes on any mode switch (including to another vt
in a different mode).