diff options
| author | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2022-02-23 14:13:03 +0100 |
|---|---|---|
| committer | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2022-02-25 18:06:27 +0100 |
| commit | cccc71b552a1040ad3d738d7ec95570801fb0bf6 (patch) | |
| tree | 4fcf3304ddb40b01370a4f8e7f3e226d041639f3 /drivers/gpu/drm/i915/display/intel_display.c | |
| parent | drm/i915: s/JSP2/ICP2/ PCH (diff) | |
| download | linux-cccc71b552a1040ad3d738d7ec95570801fb0bf6.tar.xz linux-cccc71b552a1040ad3d738d7ec95570801fb0bf6.zip | |
drm/i915: Avoid negative shift due to bigjoiner_pipes==0
bigjoiner_pipes==0 leads bigjoiner_master_pipe() to
do BIT(ffs(0)-1) which is undefined behaviour. The code should
actually still work fine since the only place we provoke
that is intel_crtc_bigjoiner_slave_pipes() and it'll bitwise
AND the result with 0, so doesn't really matter what we get
out of bigjoiner_master_pipe(). But best not provoke undefined
behaviour anyway.
Reported-by: kernel test robot <oliver.sang@intel.com>
Fixes: a6e7a006f5d5 ("drm/i915: Change bigjoiner state tracking to use the pipe bitmask")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220223131315.18016-2-ville.syrjala@linux.intel.com
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Diffstat (limited to 'drivers/gpu/drm/i915/display/intel_display.c')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_display.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index 7bf24df20b14..666f922e6f34 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -346,7 +346,10 @@ static enum pipe bigjoiner_master_pipe(const struct intel_crtc_state *crtc_state u8 intel_crtc_bigjoiner_slave_pipes(const struct intel_crtc_state *crtc_state) { - return crtc_state->bigjoiner_pipes & ~BIT(bigjoiner_master_pipe(crtc_state)); + if (crtc_state->bigjoiner_pipes) + return crtc_state->bigjoiner_pipes & ~BIT(bigjoiner_master_pipe(crtc_state)); + else + return 0; } bool intel_crtc_is_bigjoiner_slave(const struct intel_crtc_state *crtc_state) |