Replace vesadrm's code for programming the hardware gamma LUT with
DRM helpers. Either load a provided gamma ramp or program a default.
Set the individual entries with a callback.
Each gamma value is given as 3 individual 16-bit values for red,
green and blue. The driver reduces them to 8 bit to make them fit
into hardware registers.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20250520094203.30545-6-tzimmermann@suse.de
Share efidrm's and vesadrm's validation of struct screen_info in
shared helpers. Update the drivers.
Most validation helpers test individual values against limits and
can be shared as they are. For color formats, a common helper looks
up the correct DRM format info from a driver-provided list of color
formats.
These screen_info helpers are only available if CONFIG_SCREEN_INFO
has been selected, as done by efidrm and vesadrm.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20250410083834.10810-4-tzimmermann@suse.de
Add palette support and export GAMMA properties via sysfs. User-space
compositors can use this interface for programming gamma ramps or night
mode.
Vesadrm supports palette updates via VGA DAC registers or VESA palette
calls. Up to 256 palette entries are available. Userspace always supplies
gamma ramps of 256 entries. If the native color format does not match
this because pixel component have less then 8 bits, vesadrm interpolates
among the palette entries.
The code uses CamelCase style in a few places to match the VESA manuals.
v3:
- fix coding style
v2:
- use CONFIG_X86_32 instead of __i386__ (checkpatch)
- protect struct vesadrm.pmi with CONFIG_X86_32
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20250401094056.32904-19-tzimmermann@suse.de
Enable the connector's EDID property if edid_info contains valid
data. Exports the EDID via sysfs for user-space compositors.
EDID information is not always available. Depending on the system
and kernel configuration, it is either provided by the boot loader
or read by the kernel during early boot stages.
There's only one VESA display, so EDID data always belongs to this
output.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20250401094056.32904-18-tzimmermann@suse.de
Add support for screen_info setups with VIDEO_TYPE_VLFB. Provide the
minimum functionality of reading modes, updating and clearing the display.
There is existing support for these displays provided by simpledrm with
CONFIG_SYSFB_SIMPLEFB=y. Using vesadrm over simpledrm will allow for the
use of additional functionality provided by VESA, such as EDID information,
gamma correction and palette modes. This enhances the user experience and
adds support for more display configuratons.
v4:
- depend on CONFIG_X86
v3:
- depend on !SYSFB_SIMPLEFB (Javier)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20250401094056.32904-17-tzimmermann@suse.de
