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* [PATCH linux-next] drm/i915/display: Remove unused variable and its assignment.
@ 2021-10-18  8:43 ` luo penghao
  0 siblings, 0 replies; 11+ messages in thread
From: luo penghao @ 2021-10-18  8:43 UTC (permalink / raw)
  To: Jani Nikula
  Cc: Joonas Lahtinen, Rodrigo Vivi, David Airlie, Daniel Vetter,
	Stephen Rothwell, intel-gfx, dri-devel, linux-kernel,
	luo penghao, Zeal Robot

Variable is not used in functions, and its assignment is redundant too.
So it should be deleted.

The clang_analyzer complains as follows:

drivers/gpu/drm/i915/display/intel_dpll.c:1653:2 warning:
Value stored to 'bestm1' is never read.

drivers/gpu/drm/i915/display/intel_dpll.c:1651:2 warning:
Value stored to 'bestn' is never read.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: luo penghao <luo.penghao@zte.com.cn>
---
 drivers/gpu/drm/i915/display/intel_dpll.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dpll.c b/drivers/gpu/drm/i915/display/intel_dpll.c
index b84ed4a..28b1616 100644
--- a/drivers/gpu/drm/i915/display/intel_dpll.c
+++ b/drivers/gpu/drm/i915/display/intel_dpll.c
@@ -1644,13 +1644,11 @@ static void chv_prepare_pll(const struct intel_crtc_state *crtc_state)
 	enum pipe pipe = crtc->pipe;
 	enum dpio_channel port = vlv_pipe_to_channel(pipe);
 	u32 loopfilter, tribuf_calcntr;
-	u32 bestn, bestm1, bestm2, bestp1, bestp2, bestm2_frac;
+	u32 bestm2, bestp1, bestp2, bestm2_frac;
 	u32 dpio_val;
 	int vco;
 
-	bestn = crtc_state->dpll.n;
 	bestm2_frac = crtc_state->dpll.m2 & 0x3fffff;
-	bestm1 = crtc_state->dpll.m1;
 	bestm2 = crtc_state->dpll.m2 >> 22;
 	bestp1 = crtc_state->dpll.p1;
 	bestp2 = crtc_state->dpll.p2;
-- 
2.15.2


^ permalink raw reply related	[flat|nested] 11+ messages in thread
* Re:[PATCH linux-next] drm/i915/display: Remove unused variable and its assignment.
@ 2021-10-19  2:23 luo.penghao
  0 siblings, 0 replies; 11+ messages in thread
From: luo.penghao @ 2021-10-19  2:23 UTC (permalink / raw)
  To: ville.syrjala
  Cc: cgel.zte, jani.nikula, joonas.lahtinen, rodrigo.vivi, airlied,
	daniel, sfr, intel-gfx, dri-devel, zealci


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> This one we could use. For some reason we hardcode it to



> 1 now, which is correct for our use cases but I don't really> see a reason to hardcode it here. We are supposed to calculate> it correctly after all, and chv_crtc_clock_get() also just blindly> reads it out.> > >      bestm2_frac = crtc_state->dpll.m2 & 0x3fffff;> > -    bestm1 = crtc_state->dpll.m1;> > This one is a bit trickier since I don't think the spec even> gives us other values. But we could assert that it's correct.> > Some something along these lines I think would be best:> + drm_WARN_ON(&dev_priv->drm, bestm1 != 2);>   vlv_dpio_write(dev_priv, pipe, CHV_PLL_DW1(port),>                  DPIO_CHV_M1_DIV_BY_2 |> -          1 << DPIO_CHV_N_DIV_SHIFT);> +          bestn << DPIO_CHV_N_DIV_SHIFT);






Thanks for your kind response ! Does that means the variable will be


used by the hardware？if so as far as I see it, I don't seem to see the


relevant interface.

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^ permalink raw reply	[flat|nested] 11+ messages in thread
* Re:[PATCH linux-next] drm/i915/display: Remove unused variable and its assignment.
@ 2021-10-19  2:24 luo.penghao
  0 siblings, 0 replies; 11+ messages in thread
From: luo.penghao @ 2021-10-19  2:24 UTC (permalink / raw)
  To: ville.syrjala
  Cc: cgel.zte, jani.nikula, joonas.lahtinen, rodrigo.vivi, airlied,
	daniel, sfr, intel-gfx, dri-devel


[-- Attachment #1.1.1: Type: text/plain, Size: 963 bytes --]

> This one we could use. For some reason we hardcode it to



> 1 now, which is correct for our use cases but I don't really> see a reason to hardcode it here. We are supposed to calculate> it correctly after all, and chv_crtc_clock_get() also just blindly> reads it out.> > >      bestm2_frac = crtc_state->dpll.m2 & 0x3fffff;> > -    bestm1 = crtc_state->dpll.m1;> > This one is a bit trickier since I don't think the spec even> gives us other values. But we could assert that it's correct.> > Some something along these lines I think would be best:> + drm_WARN_ON(&dev_priv->drm, bestm1 != 2);>   vlv_dpio_write(dev_priv, pipe, CHV_PLL_DW1(port),>                  DPIO_CHV_M1_DIV_BY_2 |> -          1 << DPIO_CHV_N_DIV_SHIFT);> +          bestn << DPIO_CHV_N_DIV_SHIFT);






Thanks for your kind response ! Does that means the variable will be


used by the hardware？if so as far as I see it, I don't seem to see the


relevant interface.

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^ permalink raw reply	[flat|nested] 11+ messages in thread
end of thread, other threads:[~2021-10-19 12:40 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-10-18  8:43 [PATCH linux-next] drm/i915/display: Remove unused variable and its assignment luo penghao
2021-10-18  8:43 ` [Intel-gfx] " luo penghao
2021-10-18  8:57 ` Ville Syrjälä
2021-10-18  8:57   ` [Intel-gfx] " Ville Syrjälä
2021-10-19  2:22   ` luo.penghao
2021-10-19  2:22     ` [Intel-gfx] [PATCH " luo.penghao
2021-10-18 16:57 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for " Patchwork
2021-10-18 17:23 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2021-10-18 23:02 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2021-10-19  2:23 Re:[PATCH linux-next] " luo.penghao
2021-10-19  2:24 luo.penghao

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