[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-Id: <20230418183325.2327-1-pa@panix.com>
Date: Tue, 18 Apr 2023 14:33:25 -0400
From: Pierre Asselin <pa@...ix.com>
To: dri-devel@...ts.freedesktop.org
Cc: Pierre Asselin <pa@...ix.com>,
Javier Martinez Canillas <javierm@...hat.com>,
Thomas Zimmermann <tzimmermann@...e.de>,
Daniel Vetter <daniel.vetter@...ll.ch>,
Ard Biesheuvel <ardb@...nel.org>,
Hans de Goede <hdegoede@...hat.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH] firmware/sysfb: Fix VESA format selection
Some legacy BIOSes report no reserved bits in their 32-bit rgb mode,
breaking the calculation of bits_per_pixel in commit f35cd3fa7729
[firmware/sysfb: Fix EFI/VESA format selection]. However they report
lfb_depth correctly for those modes. Recompute bits_per_pixel from the
color and reserved bit numbers and positions, but also from lfb_depth,
keeping the larger result.
Link: https://lore.kernel.org/r/4Psm6B6Lqkz1QXM@panix3.panix.com
Link: https://lore.kernel.org/r/20230412150225.3757223-1-javierm@redhat.com
Fixes: f35cd3fa7729 [firmware/sysfb: Fix EFI/VESA format selection]
Signed-off-by: Pierre Asselin <pa@...ix.com>
---
drivers/firmware/sysfb_simplefb.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c
index 82c64cb9f531..05dc25a524c8 100644
--- a/drivers/firmware/sysfb_simplefb.c
+++ b/drivers/firmware/sysfb_simplefb.c
@@ -51,15 +51,17 @@ __init bool sysfb_parse_mode(const struct screen_info *si,
*
* It's not easily possible to fix this in struct screen_info,
* as this could break UAPI. The best solution is to compute
- * bits_per_pixel here and ignore lfb_depth. In the loop below,
+ * bits_per_pixel from the color bits, reserved bits and
+ * reported lfb_depth, whichever is highest. In the loop below,
* ignore simplefb formats with alpha bits, as EFI and VESA
* don't specify alpha channels.
*/
if (si->lfb_depth > 8) {
- bits_per_pixel = max(max3(si->red_size + si->red_pos,
+ bits_per_pixel = max3(max3(si->red_size + si->red_pos,
si->green_size + si->green_pos,
si->blue_size + si->blue_pos),
- si->rsvd_size + si->rsvd_pos);
+ si->rsvd_size + si->rsvd_pos,
+ si->lfb_depth);
} else {
bits_per_pixel = si->lfb_depth;
}
--
2.39.2
Powered by blists - more mailing lists