Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
From:   Kees Cook <keescook@google.com>
Date:   Wed, 22 Nov 2017 12:54:49 -0800
Message-ID: <CAGXu5jJ3Sa8Kj7JSFBfKn=35FSyGnimKvq2ES6u84Axvbo_BQg@mail.gmail.com>
Subject: i915: enum intel_dpll_id cast
To:     Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc:     Mika Kahola <mika.kahola@intel.com>,
        intel-gfx@lists.freedesktop.org,
        LKML <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi,

While doing Clang test builds, this was reported:

drivers/gpu/drm/i915/intel_ddi.c:1481:30: warning: implicit conversion
from enumeration type 'enum port' to different enumeration type 'enum
intel_dpll_id' [-Wenum-conversion]
        enum intel_dpll_id pll_id = port;
                           ~~~~~~   ^~~~

Which is from:

static void bxt_ddi_clock_get(struct intel_encoder *encoder,
                                struct intel_crtc_state *pipe_config)
{
        struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
        enum port port = intel_ddi_get_encoder_port(encoder);
        enum intel_dpll_id pll_id = port;

        pipe_config->port_clock = bxt_calc_pll_link(dev_priv, pll_id);
...
}

In looking at it, it seems to be harmless if as enum port has a
smaller range than enum intel_dpll_id. I just wanted to check if maybe
something might go weird, since DPLL_ID_LCPLL_2700 maybe ends up
getting seen as I915_MAX_PORTS?

enum port {
        PORT_NONE = -1,
        PORT_A = 0,
        PORT_B,
        PORT_C,
        PORT_D,
        PORT_E,
        I915_MAX_PORTS
};

enum intel_dpll_id {
...
        DPLL_ID_LCPLL_2700 = 5,
...
};


Thanks!

-Kees

-- 
Kees Cook
Pixel Security

From 1584886338268453018@xxx Thu Nov 23 19:29:55 +0000 2017
X-GM-THRID: 1584886338268453018
X-Gmail-Labels: Inbox,Category Forums,HistoricalUnread