From: Stephen Boyd <sboyd@kernel.org>
To: Maxime Ripard <maxime@cerno.tech>,
Michael Turquette <mturquette@baylibre.com>
Cc: linux-kernel@vger.kernel.org,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com>,
Maxime Ripard <maxime@cerno.tech>,
linux-clk@vger.kernel.org
Subject: Re: [PATCH 1/4] clk: Remove WARN_ON NULL parent in clk_core_init_rate_req()
Date: Thu, 27 Oct 2022 17:06:37 -0700 [thread overview]
Message-ID: <20221028000639.9E2BAC433B5@smtp.kernel.org> (raw)
In-Reply-To: <20221018-clk-range-checks-fixes-v1-1-f3ef80518140@cerno.tech>
Quoting Maxime Ripard (2022-10-18 06:52:56)
> If a clock has CLK_SET_RATE_PARENT, but core->parent is NULL (most
> likely because it's orphan), callers of clk_core_init_rate_req() will
> blindly call this function leading to a very verbose warning.
>
> Since it's a fairly common situation, let's just remove the WARN_ON but
> keep the check that prevents us from dereferencing the pointer.
>
> Interestingly, it fixes a regression on the Mediatek MT8195 where the
> GPU would stall during a clk_set_rate for its main clock. We couldn't
> come up with a proper explanation since the condition is essentially the
> same.
>
> It was then assumed that it could be timing related since printing the
> warning stacktrace takes a while, but we couldn't replicate the failure
> by using fairly large (10ms) mdelays.
>
> Fixes: 262ca38f4b6e ("clk: Stop forwarding clk_rate_requests to the parent")
> Reported-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> ---
Applied to clk-fixes
next prev parent reply other threads:[~2022-10-28 0:06 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-18 13:52 [PATCH 0/4] clk: Rate range improvements Maxime Ripard
2022-10-18 13:52 ` [PATCH 1/4] clk: Remove WARN_ON NULL parent in clk_core_init_rate_req() Maxime Ripard
2022-10-18 14:35 ` AngeloGioacchino Del Regno
2022-10-28 0:06 ` Stephen Boyd [this message]
2022-10-18 13:52 ` [PATCH 2/4] clk: Initialize the clk_rate_request even if clk_core is NULL Maxime Ripard
2022-10-18 14:35 ` AngeloGioacchino Del Regno
2022-10-28 0:09 ` Stephen Boyd
2022-10-18 13:52 ` [PATCH 3/4] clk: Initialize max_rate in struct clk_rate_request Maxime Ripard
2022-10-18 14:35 ` AngeloGioacchino Del Regno
2022-10-28 0:09 ` Stephen Boyd
2022-10-18 13:52 ` [PATCH 4/4] clk: Warn if we register a mux without determine_rate Maxime Ripard
2022-10-18 14:34 ` AngeloGioacchino Del Regno
2022-10-26 2:07 ` Stephen Boyd
2022-10-26 13:52 ` maxime
2022-10-27 21:45 ` Stephen Boyd
2022-11-03 12:39 ` Maxime Ripard
2022-11-03 12:33 ` Maxime Ripard
2022-11-04 18:10 ` Stephen Boyd
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=20221028000639.9E2BAC433B5@smtp.kernel.org \
--to=sboyd@kernel.org \
--cc=angelogioacchino.delregno@collabora.com \
--cc=linux-clk@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=maxime@cerno.tech \
--cc=mturquette@baylibre.com \
/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;
as well as URLs for NNTP newsgroup(s).