On Wed, 03 Sep 2025, "Kahola, Mika" <[email protected]> wrote:
> Ok good to know. Let's just ignore this patch.
That said, all places that use bxt_port_to_phy_channel(),
vlv_dig_port_to_channel(), vlv_dig_port_to_phy(), vlv_pipe_to_channel(),
or vlv_pipe_to_phy() need *both* the phy and channel.
So I'm thinking you could add
struct {
enum dpio_phy phy;
enum dpio_channel channel;
} dpio_phy_channel;
and convert the above functions to always return that struct. It's small
enough to return as a whole. Something like:
struct dpio_phy_channel phy_channel;
phy_channel = bxt_port_to_phy_channel(display, port);
and
phy_channel = vlv_dig_port_to_phy_channel(dig_port);
and
phy_channel = vlv_pipe_to_phy_channel(pipe);
Then you can also do s/phy/phy_channel.phy/ and s/ch/phy_channel.ch/ as
cleanup (if it actually cleans things up, maybe not).
Bonus points if you can come up with a better name than
"phy_channel". ;)
With that, the interface gets reduced for vlv, and it's obvious to
static analyzers the stuff gets initialized. Win-win?
BR,
Jani.
>
> Thanks!
>
> -Mika-
>
>> -----Original Message-----
>> From: Jani Nikula <[email protected]>
>> Sent: Wednesday, 3 September 2025 15.19
>> To: Kahola, Mika <[email protected]>; [email protected];
>> [email protected]
>> Cc: Kahola, Mika <[email protected]>
>> Subject: Re: [PATCH] drm/i915/display: Initialize phy and ch variables
>>
>> On Wed, 03 Sep 2025, Mika Kahola <[email protected]> wrote:
>> > phy and ch variables are potentially used uninitialized.
>>
>> They're not, bxt_port_to_phy_channel() initializes them in all code paths.
>>
>> > To make absolutely sure that these variables are not used
>> > uninitialized let's initialize these with known values as
>> > DPIO_PHY0 and DPIO_CH0, respectively.
>> >
>> > Signed-off-by: Mika Kahola <[email protected]>
>> > ---
>> > drivers/gpu/drm/i915/display/intel_dpll_mgr.c | 4 ++--
>> > 1 file changed, 2 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
>> > b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
>> > index 8ea96cc524a1..45b67a3716e9 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
>> > +++ b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c
>> > @@ -2174,8 +2174,8 @@ static bool bxt_ddi_pll_get_hw_state(struct
>> > intel_display *display,
>> > struct bxt_dpll_hw_state *hw_state = &dpll_hw_state->bxt;
>> > enum port port = (enum port)pll->info->id; /* 1:1 port->PLL mapping */
>> > intel_wakeref_t wakeref;
>> > - enum dpio_phy phy;
>> > - enum dpio_channel ch;
>> > + enum dpio_phy phy = DPIO_PHY0;
>> > + enum dpio_channel ch = DPIO_CH0;
>> > u32 val;
>> > bool ret;
>>
>> --
>> Jani Nikula, Intel
--
Jani Nikula, Intel
