Igt-dev Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: Alex Hung <alex.hung@amd.com>
To: <igt-dev@lists.freedesktop.org>
Cc: brian.starkey@arm.com, maxime@cerno.tech
Subject: [igt-dev] [PATCH 1/3] lib/igt_fb: use the entire 32 bit for fnv1a_crc
Date: Wed, 16 Aug 2023 14:53:14 -0600	[thread overview]
Message-ID: <20230816205316.867195-1-alex.hung@amd.com> (raw)

The function was implemented as a 32-bit hashing function. Commit
85f4c1005150 ("lib/igt_fb: Ignore the X component when computing CRC")
broke this behavior by hashing 8-bit portions. Restore the 32-bit hasing
behavior while still ignoring the X compoment.

Signed-off-by: Alex Hung <alex.hung@amd.com>
---
 lib/igt_fb.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/lib/igt_fb.c b/lib/igt_fb.c
index 60b0e2669..9beb07049 100644
--- a/lib/igt_fb.c
+++ b/lib/igt_fb.c
@@ -4780,16 +4780,11 @@ int igt_fb_get_fnv1a_crc(struct igt_fb *fb, igt_crc_t *crc)
 		igt_memcpy_from_wc(line, ptr, fb->width * cpp);
 
 		for (x = 0; x < fb->width; x++) {
-			unsigned int i;
 			uint32_t pixel = le32_to_cpu(line[x]);
 			pixel &= 0x00ffffff;
 
-			for (i = 0; i < sizeof(pixel); i++) {
-				uint8_t component = (pixel >> (i * 8)) & 0xff;
-
-				hash ^= component;
-				hash *= FNV1a_PRIME;
-			}
+			hash ^= pixel;
+			hash *= FNV1a_PRIME;
 		}
 	}
 
-- 
2.34.1

             reply	other threads:[~2023-08-16 20:53 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-16 20:53 Alex Hung [this message]
2023-08-16 20:53 ` [igt-dev] [PATCH 2/3] lib/igt_fb: add 10 bits (XRGB2101010) supports in fnv1a_crc Alex Hung
2023-08-16 20:53 ` [igt-dev] [PATCH 3/3] tests/kms_writeback: support DRM_FORMAT_XRGB2101010 for writeback Alex Hung
2023-08-17  6:32   ` Maxime Ripard
2023-08-17  7:09     ` Alex Hung
2023-08-17  7:50       ` Maxime Ripard
2023-08-17 14:15         ` Harry Wentland
2023-08-17 16:22           ` Alex Hung
2023-08-22 14:14             ` Maxime Ripard
2023-08-22 14:34               ` Harry Wentland
2023-08-22 13:26           ` Maxime Ripard
2023-08-22 14:51             ` Harry Wentland
2023-08-16 23:41 ` [igt-dev] ○ CI.xeBAT: info for series starting with [1/3] lib/igt_fb: use the entire 32 bit for fnv1a_crc Patchwork
2023-08-16 23:47 ` [igt-dev] ✓ Fi.CI.BAT: success " Patchwork
2023-08-17 11:13 ` [igt-dev] ✓ Fi.CI.IGT: " Patchwork

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20230816205316.867195-1-alex.hung@amd.com \
    --to=alex.hung@amd.com \
    --cc=brian.starkey@arm.com \
    --cc=igt-dev@lists.freedesktop.org \
    --cc=maxime@cerno.tech \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox