From 46b3c0f683d6a2128f7f2bf236bcdc62caec5c83 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Wed, 15 Feb 2023 17:01:29 +0200 Subject: [PATCH] drm/i915: Reduce ELD hex dumps a bit MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20230215150129.13288-1-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula --- 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 c355ee01d4db1..92dbb83a531bc 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -5344,6 +5344,20 @@ 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, @@ -5353,6 +5367,9 @@ 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, @@ -5360,6 +5377,9 @@ 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); -- 2.30.2