diff options
| author | Samasth Norway Ananda <samasth.norway.ananda@oracle.com> | 2026-03-16 16:19:19 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-04-02 13:25:34 +0200 |
| commit | dcf889956682d801d4a021a0f8bf34596bcf61c8 (patch) | |
| tree | f5fa2b11ecf429377145117b9dfac5c64850de49 /drivers/gpu | |
| parent | df03f5ac1eae7c5a2c01846e3e64dfc2870eec6b (diff) | |
drm/i915/gmbus: fix spurious timeout on 512-byte burst reads
[ Upstream commit 08441f10f4dc09fdeb64529953ac308abc79dd38 ]
When reading exactly 512 bytes with burst read enabled, the
extra_byte_added path breaks out of the inner do-while without
decrementing len. The outer while(len) then re-enters and gmbus_wait()
times out since all data has been delivered. Decrement len before the
break so the outer loop terminates correctly.
Fixes: d5dc0f43f268 ("drm/i915/gmbus: Enable burst read")
Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patch.msgid.link/20260316231920.135438-2-samasth.norway.ananda@oracle.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit 4ab0f09ee73fc853d00466682635f67c531f909c)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_gmbus.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_gmbus.c b/drivers/gpu/drm/i915/display/intel_gmbus.c index 795012d7c24c..5a941bea81ca 100644 --- a/drivers/gpu/drm/i915/display/intel_gmbus.c +++ b/drivers/gpu/drm/i915/display/intel_gmbus.c @@ -498,8 +498,10 @@ gmbus_xfer_read_chunk(struct intel_display *display, val = intel_de_read_fw(display, GMBUS3(display)); do { - if (extra_byte_added && len == 1) + if (extra_byte_added && len == 1) { + len--; break; + } *buf++ = val & 0xff; val >>= 8; |