From: Ville Syrjälä <[email protected]> Do the ELD hexdumps only up to the last differing byte. The rest is typically all zeroes anyway so not much point in dumping it.
Couldn't find anything for memcmp_diff_len() so rolled my own. v2: Use semantics and function name suggested by Jani Cc: Jani Nikula <[email protected]> Signed-off-by: Ville Syrjälä <[email protected]> --- drivers/gpu/drm/i915/display/intel_display.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index 3479125fbda6..664322a58236 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -5348,6 +5348,20 @@ pipe_config_dp_vsc_sdp_mismatch(struct drm_i915_private *dev_priv, } } +/* Returns the length up to and including the last differing byte */ +static size_t +memcmp_diff_len(const u8 *a, const u8 *b, size_t len) +{ + int i; + + for (i = len - 1; i >= 0; i--) { + if (a[i] != b[i]) + return i + 1; + } + + return 0; +} + static void pipe_config_buffer_mismatch(struct drm_i915_private *dev_priv, bool fastset, const char *name, @@ -5357,6 +5371,9 @@ pipe_config_buffer_mismatch(struct drm_i915_private *dev_priv, if (!drm_debug_enabled(DRM_UT_KMS)) return; + /* only dump up to the last difference */ + len = memcmp_diff_len(a, b, len); + drm_dbg_kms(&dev_priv->drm, "fastset mismatch in %s buffer\n", name); print_hex_dump(KERN_DEBUG, "expected: ", DUMP_PREFIX_NONE, @@ -5364,6 +5381,9 @@ pipe_config_buffer_mismatch(struct drm_i915_private *dev_priv, print_hex_dump(KERN_DEBUG, "found: ", DUMP_PREFIX_NONE, 16, 0, b, len, false); } else { + /* only dump up to the last difference */ + len = memcmp_diff_len(a, b, len); + drm_err(&dev_priv->drm, "mismatch in %s buffer\n", name); print_hex_dump(KERN_ERR, "expected: ", DUMP_PREFIX_NONE, 16, 0, a, len, false); -- 2.39.1
