Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
Am 19.04.23 um 06:48 schrieb Pierre Asselin:
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?
A friendly note from a robot; make W=1 sysfb_simplefb.o .
https://lore.kernel.org/dri-devel/20230418183325.2327-1-pa@xxxxxxxxx/T/#m38e859354329ab9f756da91e99b546e3b140fa91
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);
Would that work? If I understand correctly max3() checks that all args
have the same type. {red,green,blue,rsvd}.{size,pos} are all u8 while
lfb_depth is u16. The best I can do is
bits_per_pixel = max3((u16)max3(si->red_size + si->red_pos,
si->green_size + si->green_pos,
si->blue_size + si->blue_pos),
(u16)(si->rsvd_size + si->rsvd_pos),
si->lfb_depth);
That compiles quietly with W=1 but those two casts are ugly.
If I do that, would K&R-on-parentheses read better ?
bits_per_pixel = max3(
(u16)max3(
si->red_size + si->red_pos,
si->green_size + si->green_pos,
si->blue_size + si->blue_pos
),
(u16)(si->rsvd_size + si->rsvd_pos),
si->lfb_depth
);
I think it's clearer, but not kernel style and still ugly.
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().
That would be a two-patch series. I'd rather keep it to the strict
minimum that fixes the regression. (You trust me to even *look* at a
kernel header and not break it ? Dangerous assumption!)
I'm new at this. Two months ago I didn't know what to type a the
command line after "git".
Incidentally, should I send v3 as a new email or reply to the chain?
--PA
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