Only set PMI fields if the screen_info's Vesa PM segment has been
set. Vesa PMI is the power-management interface. It also provides
means to set the color palette. The interface is optional, so not
all VESA graphics cards support it. Print vesafb's warning [1] if
the hardware palette cannot be set at all.
If unsupported the field PrimaryPalette in struct vesadrm.pmi is
NULL, which results in a segmentation fault. Happens with qemu's
Cirrus emulation.
Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de>
Fixes: 814d270b31d2 ("drm/sysfb: vesadrm: Add gamma correction")
Link:
https://elixir.bootlin.com/linux/v6.15/source/drivers/video/fbdev/vesafb.c#L375
# 1
Cc: Thomas Zimmermann <tzimmerm...@suse.de>
Cc: Javier Martinez Canillas <javi...@redhat.com>
Cc: dri-devel@lists.freedesktop.org
---
drivers/gpu/drm/sysfb/vesadrm.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/sysfb/vesadrm.c b/drivers/gpu/drm/sysfb/vesadrm.c
index c5216dbe21ec..074d2bae9db3 100644
--- a/drivers/gpu/drm/sysfb/vesadrm.c
+++ b/drivers/gpu/drm/sysfb/vesadrm.c
@@ -334,14 +334,19 @@ static struct vesadrm_device
*vesadrm_device_create(struct drm_driver *drv,
if (!__screen_info_vbe_mode_nonvga(si)) {
vesa->cmap_write = vesadrm_vga_cmap_write;
-#if defined(CONFIG_X86_32)
} else {
+#if defined(CONFIG_X86_32)
phys_addr_t pmi_base = __screen_info_vesapm_info_base(si);
- const u16 *pmi_addr = phys_to_virt(pmi_base);
- vesa->pmi.PrimaryPalette = (u8 *)pmi_addr + pmi_addr[2];
- vesa->cmap_write = vesadrm_pmi_cmap_write;
+ if (pmi_base) {
+ const u16 *pmi_addr = phys_to_virt(pmi_base);
+
+ vesa->pmi.PrimaryPalette = (u8 *)pmi_addr + pmi_addr[2];
+ vesa->cmap_write = vesadrm_pmi_cmap_write;
+ } else
#endif
+ if (format->is_color_indexed)
+ drm_warn(dev, "hardware palette is unchangeable, colors
may be incorrect\n");
}
#if defined(CONFIG_FIRMWARE_EDID)
--
2.49.0
