linux-kernel - Re: [PATCH 2/4] clk: qcom: Add clk_rcg2_gfx3d

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <153324986956.10763.5124619734269160725@swboyd.mtv.corp.google.com>
Date:   Thu, 02 Aug 2018 15:44:29 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Amit Nischal <anischal@...eaurora.org>
Cc:     Michael Turquette <mturquette@...libre.com>,
        Andy Gross <andy.gross@...aro.org>,
        David Brown <david.brown@...aro.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Odelu Kukatla <okukatla@...eaurora.org>,
        Taniya Das <tdas@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-clk-owner@...r.kernel.org
Subject: Re: [PATCH 2/4] clk: qcom: Add clk_rcg2_gfx3d_ops for SDM845

Quoting Amit Nischal (2018-07-30 04:28:56)
> On 2018-07-25 12:28, Stephen Boyd wrote:
> > 
> > Ok. Sounds good! Is the rate range call really needed? It can't be
> > determined in the PLL code with some table or avoided by making sure 
> > GPU
> > uses OPP table with only approved frequencies?
> > 
> 
> Currently fabia PLL code does not have any table to check this and 
> intention
> was to avoid relying on the client to call set_rate with only approved
> frequencies so we have added the set_rate_range() call in the GPUCC 
> driver
> in order to set the rate range.
> 

But GPU will use OPP so it doesn't seem like it really buys us anything
here. And it really doesn't matter when the clk driver implementation
doesn't use the min/max to clamp the values of the round_rate() call. Is
that being done here? I need to double check. I would be more convinced
if the implementation was looking at min/max to constrain the rate
requested.