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Commit 32bc70b7 authored by Colin Ian King's avatar Colin Ian King Committed by Greg Kroah-Hartman
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video: fbdev: vga16fb: fix setting of pixclock because a pass-by-value error 

[ Upstream commit c72fab81ceaa54408b827a2f0486d9a0f4be34cf ]

The pixclock is being set locally because it is being passed as a
pass-by-value argument rather than pass-by-reference, so the computed
pixclock is never being set in var->pixclock. Fix this by passing
by reference.

[This dates back to 2002, I found the offending commit from the git
history git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git

 ]

Addresses-Coverity: ("Unused value")
Signed-off-by: default avatarColin Ian King <colin.king@canonical.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@intel.com>
[b.zolnierkie: minor patch summary fixup]
[b.zolnierkie: removed "Fixes:" tag (not in upstream tree)]
Signed-off-by: default avatarBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200723170227.996229-1-colin.king@canonical.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 34a50078

drivers/video/fbdev/vga16fb.c

+7 −7
Original line number Diff line number Diff line
@@ -243,7 +243,7 @@ static void vga16fb_update_fix(struct fb_info *info) 
}



static void vga16fb_clock_chip(struct vga16fb_par *par,

			       unsigned int pixclock,

			       unsigned int *pixclock,

			       const struct fb_info *info,

			       int mul, int div)

{
@@ -259,14 +259,14 @@ static void vga16fb_clock_chip(struct vga16fb_par *par, 
		{     0 /* bad */,    0x00, 0x00}};

	int err;



	pixclock = (pixclock * mul) / div;

	*pixclock = (*pixclock * mul) / div;

	best = vgaclocks;

	err = pixclock - best->pixclock;

	err = *pixclock - best->pixclock;

	if (err < 0) err = -err;

	for (ptr = vgaclocks + 1; ptr->pixclock; ptr++) {

		int tmp;



		tmp = pixclock - ptr->pixclock;

		tmp = *pixclock - ptr->pixclock;

		if (tmp < 0) tmp = -tmp;

		if (tmp < err) {

			err = tmp;
@@ -275,7 +275,7 @@ static void vga16fb_clock_chip(struct vga16fb_par *par, 
	}

	par->misc |= best->misc;

	par->clkdiv = best->seq_clock_mode;

	pixclock = (best->pixclock * div) / mul;		

	*pixclock = (best->pixclock * div) / mul;

}

			       

#define FAIL(X) return -EINVAL
@@ -497,10 +497,10 @@ static int vga16fb_check_var(struct fb_var_screeninfo *var, 


	if (mode & MODE_8BPP)

		/* pixel clock == vga clock / 2 */

		vga16fb_clock_chip(par, var->pixclock, info, 1, 2);

		vga16fb_clock_chip(par, &var->pixclock, info, 1, 2);

	else

		/* pixel clock == vga clock */

		vga16fb_clock_chip(par, var->pixclock, info, 1, 1);

		vga16fb_clock_chip(par, &var->pixclock, info, 1, 1);

	

	var->red.offset = var->green.offset = var->blue.offset = 

	var->transp.offset = 0;