| Message ID | 20201103221510.575827-1-lyude@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] drm/edid: Fix uninitialized variable in drm_cvt_modes() | expand |
On Tue, Nov 3, 2020 at 5:15 PM Lyude Paul <lyude@redhat.com> wrote: > > Noticed this when trying to compile with -Wall on a kernel fork. We potentially > don't set width here, which causes the compiler to complain about width > potentially being uninitialized in drm_cvt_modes(). So, let's fix that. > > Changes since v1: > * Don't emit an error as this code isn't reachable, just mark it as such > > Signed-off-by: Lyude Paul <lyude@redhat.com> > > Cc: <stable@vger.kernel.org> # v5.9+ > Fixes: 3f649ab728cd ("treewide: Remove uninitialized_var() usage") > Signed-off-by: Lyude Paul <lyude@redhat.com> > --- > drivers/gpu/drm/drm_edid.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 631125b46e04..0643b98c6383 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -3094,6 +3094,7 @@ static int drm_cvt_modes(struct drm_connector *connector, > > for (i = 0; i < 4; i++) { > int width, height; > + u8 cvt_aspect_ratio; > > cvt = &(timing->data.other_data.data.cvt[i]); > > @@ -3101,7 +3102,8 @@ static int drm_cvt_modes(struct drm_connector *connector, > continue; > > height = (cvt->code[0] + ((cvt->code[1] & 0xf0) << 4) + 1) * 2; > - switch (cvt->code[1] & 0x0c) { > + cvt_aspect_ratio = cvt->code[1] & 0x0c; The temp var doesn't do anything now right? Previously you were using it in the print, but now you can drop these two hunks, I think? -ilia > + switch (cvt_aspect_ratio) { > case 0x00: > width = height * 4 / 3; > break; > @@ -3114,6 +3116,8 @@ static int drm_cvt_modes(struct drm_connector *connector, > case 0x0c: > width = height * 15 / 9; > break; > + default: > + unreachable(); > } > > for (j = 1; j < 5; j++) { > -- > 2.28.0 >
Hi Lyude,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on drm-intel/for-linux-next]
[also build test WARNING on drm-tip/drm-tip drm-exynos/exynos-drm-next tegra-drm/drm/tegra/for-next linus/master v5.10-rc2 next-20201103]
[cannot apply to drm/drm-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Lyude-Paul/drm-edid-Fix-uninitialized-variable-in-drm_cvt_modes/20201104-061621
base: git://anongit.freedesktop.org/drm-intel for-linux-next
config: x86_64-randconfig-a011-20201104 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce (this is a W=1 build):
# https://github.com/0day-ci/linux/commit/ca77ba73371e528e2bb9e631817c614717b4f794
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Lyude-Paul/drm-edid-Fix-uninitialized-variable-in-drm_cvt_modes/20201104-061621
git checkout ca77ba73371e528e2bb9e631817c614717b4f794
# save the attached .config to linux build tree
make W=1 ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
>> drivers/gpu/drm/drm_edid.o: warning: objtool: do_cvt_mode() falls through to next function drm_mode_std.isra.0()
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 631125b46e04..0643b98c6383 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -3094,6 +3094,7 @@ static int drm_cvt_modes(struct drm_connector *connector, for (i = 0; i < 4; i++) { int width, height; + u8 cvt_aspect_ratio; cvt = &(timing->data.other_data.data.cvt[i]); @@ -3101,7 +3102,8 @@ static int drm_cvt_modes(struct drm_connector *connector, continue; height = (cvt->code[0] + ((cvt->code[1] & 0xf0) << 4) + 1) * 2; - switch (cvt->code[1] & 0x0c) { + cvt_aspect_ratio = cvt->code[1] & 0x0c; + switch (cvt_aspect_ratio) { case 0x00: width = height * 4 / 3; break; @@ -3114,6 +3116,8 @@ static int drm_cvt_modes(struct drm_connector *connector, case 0x0c: width = height * 15 / 9; break; + default: + unreachable(); } for (j = 1; j < 5; j++) {