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| author | Ronald G. Minnich <rminnich@gmail.com> | 2013-08-29 09:16:25 -0700 |
|---|---|---|
| committer | Patrick Georgi <patrick@georgi-clan.de> | 2014-08-10 22:19:16 +0200 |
| commit | cff6667eba803498e2f93af68e6e2edbba2353e5 (patch) | |
| tree | 3ec00fb2b881a702ce64d337a58295226f75e654 /src/cpu | |
| parent | 985ff36bee24d1e5a8bd698409a0a05e15528c01 (diff) | |
| download | coreboot-cff6667eba803498e2f93af68e6e2edbba2353e5.tar.xz | |
exynos5420: Tighten up displayport timing loops
We were running this loop 100 times with 5 ms delays. Change it
to run 500 times with 1 ms delays, which gives us the same
overall timeout but lets us bail out a bit sooner -- in practice,
at most, 4 ms sooner but every bit counts. Note, however, that
the tighter timing does reduce opportunities for threading. There
is a non-obvious set of tradeoffs on timeouts.
Change-Id: I4af671c2a791aa92e446e66ac2fe5710d1e6aa4c
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: https://chromium-review.googlesource.com/167387
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Commit-Queue: ron minnich <rminnich@chromium.org>
Tested-by: ron minnich <rminnich@chromium.org>
(cherry picked from commit 575e910127dc74416018f182ef27ef223e61daef)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6543
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Diffstat (limited to 'src/cpu')
| -rw-r--r-- | src/cpu/samsung/exynos5420/dp.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/cpu/samsung/exynos5420/dp.c b/src/cpu/samsung/exynos5420/dp.c index b6f83b6519..c1fa17a9c6 100644 --- a/src/cpu/samsung/exynos5420/dp.c +++ b/src/cpu/samsung/exynos5420/dp.c @@ -845,7 +845,7 @@ static unsigned int exynos_dp_config_video(struct edp_device_info *edp_info) exynos_dp_start_video(); if (edp_info->video_info.master_mode == 0) { - retry_cnt = 100; + retry_cnt = 500; while (retry_cnt) { ret = exynos_dp_is_video_stream_on(); if (ret != EXYNOS_DP_SUCCESS) { @@ -857,7 +857,10 @@ static unsigned int exynos_dp_config_video(struct edp_device_info *edp_info) printk(BIOS_DEBUG, "DP video stream is on\n"); break; } - mdelay(5); + /* this is a cheap operation, involving some register + * reads, and no AUX channel IO. A ms. delay is fine. + */ + mdelay(1); } } |