Hi Am 19.04.23 um 06:48 schrieb Pierre Asselin:
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. Keep the computation but set bits_per_pixel to lfb_depth if the latter is larger. v2 fixes the warnings from a max3() macro with arguments of different types; split the bits_per_pixel assignment to avoid uglyfing the code with too many typecasts.
What exactly was that warning?
Link: https://lore.kernel.org/r/4Psm6B6Lqkz1QXM@xxxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/20230412150225.3757223-1-javierm@xxxxxxxxxx Fixes: f35cd3fa7729 [firmware/sysfb: Fix EFI/VESA format selection] Signed-off-by: Pierre Asselin <pa@xxxxxxxxx> --- drivers/firmware/sysfb_simplefb.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c index 82c64cb9f531..358b792a8845 100644 --- a/drivers/firmware/sysfb_simplefb.c +++ b/drivers/firmware/sysfb_simplefb.c @@ -51,7 +51,8 @@ __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. */ @@ -60,6 +61,7 @@ __init bool sysfb_parse_mode(const struct screen_info *si, si->green_size + si->green_pos, si->blue_size + si->blue_pos), si->rsvd_size + si->rsvd_pos); + bits_per_pixel= max(bits_per_pixel, (u32)si->lfb_depth);
I liked the all-in-one assignment of the original patch. So I'd rather go back to v1 and copy si->lfb_depth to the correct type, like this:
u32 depth = si->lfb_depth;
bits_per_pixel = max3(max3(colors),
rsvd,
depth);
Or, if you want to get fancy, you could add max3_t() to <linux/minmax.h>
#define max3_t(type, x, y, z) max_t(type, max_t(type, x, y), z)
and do
bits_per_pixel = max3_t(u32,
max3(colors),
rsvd,
si->lfb_depth)
You could also add a max4_t(type, x, y, z, w) to <linux/minmax.h> and
compare all values with max4_t().
Best regards Thomas
} else {
bits_per_pixel = si->lfb_depth;
}
base-commit: 6a8f57ae2eb07ab39a6f0ccad60c760743051026
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev
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