[Intel-gfx] [PATCH v1] drm/i915: Fix wrong CDCLK adjustment changes

Lisovskiy, Stanislav stanislav.lisovskiy at intel.com
Mon Jun 1 14:12:41 UTC 2020


On Mon, Jun 01, 2020 at 05:01:08PM +0300, Dan Carpenter wrote:
> Hi Stanislav,
> 
> url:    https://github.com/0day-ci/linux/commits/Stanislav-Lisovskiy/drm-i915-Fix-wrong-CDCLK-adjustment-changes/20200526-180642
> base:   git://anongit.freedesktop.org/drm/drm-tip drm-tip
> config: i386-randconfig-m021-20200531 (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-13) 9.3.0
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kbuild test robot <lkp at intel.com>
> Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
> 
> smatch warnings:
> drivers/gpu/drm/i915/display/intel_bw.c:453 skl_bw_calc_min_cdclk() error: uninitialized symbol 'pipe'.
> 
> # https://github.com/0day-ci/linux/commit/21b0324886122a396687d977d67eb6ce3caf2b17
> git remote add linux-review https://github.com/0day-ci/linux
> git remote update linux-review
> git checkout 21b0324886122a396687d977d67eb6ce3caf2b17
> vim +/pipe +453 drivers/gpu/drm/i915/display/intel_bw.c
> 
> 366b6200f76e0f Jani Nikula         2019-08-06  430  
> cd19154608610a Stanislav Lisovskiy 2020-05-20  431  int skl_bw_calc_min_cdclk(struct intel_atomic_state *state)
> cd19154608610a Stanislav Lisovskiy 2020-05-20  432  {
> cd19154608610a Stanislav Lisovskiy 2020-05-20  433  	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  434  	struct intel_bw_state *new_bw_state = NULL;
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  435  	struct intel_bw_state *old_bw_state = NULL;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  436  	const struct intel_crtc_state *crtc_state;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  437  	struct intel_crtc *crtc;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  438  	int max_bw = 0;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  439  	int slice_id;
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  440  	enum pipe pipe;
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  441  	int i;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  442  
> cd19154608610a Stanislav Lisovskiy 2020-05-20  443  	for_each_new_intel_crtc_in_state(state, crtc, crtc_state, i) {
> cd19154608610a Stanislav Lisovskiy 2020-05-20  444  		enum plane_id plane_id;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  445  		struct intel_dbuf_bw *crtc_bw;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  446  
> cd19154608610a Stanislav Lisovskiy 2020-05-20  447  		new_bw_state = intel_atomic_get_bw_state(state);
> cd19154608610a Stanislav Lisovskiy 2020-05-20  448  		if (IS_ERR(new_bw_state))
> cd19154608610a Stanislav Lisovskiy 2020-05-20  449  			return PTR_ERR(new_bw_state);
> cd19154608610a Stanislav Lisovskiy 2020-05-20  450  
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  451  		old_bw_state = intel_atomic_get_old_bw_state(state);
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  452  
> 21b0324886122a Stanislav Lisovskiy 2020-05-26 @453  		crtc_bw = &new_bw_state->dbuf_bw[pipe];
>                                                                                                  ^^^^
> Not initialized.  Probably "i" was intended?

Ahh.. Rather silly typo - it should be crtc->pipe.
Thanks for spotting.

Stan

> 
> cd19154608610a Stanislav Lisovskiy 2020-05-20  454  
> cd19154608610a Stanislav Lisovskiy 2020-05-20  455  		memset(&crtc_bw->used_bw, 0, sizeof(crtc_bw->used_bw));
> cd19154608610a Stanislav Lisovskiy 2020-05-20  456  
> cd19154608610a Stanislav Lisovskiy 2020-05-20  457  		for_each_plane_id_on_crtc(crtc, plane_id) {
> cd19154608610a Stanislav Lisovskiy 2020-05-20  458  			const struct skl_ddb_entry *plane_alloc =
> cd19154608610a Stanislav Lisovskiy 2020-05-20  459  				&crtc_state->wm.skl.plane_ddb_y[plane_id];
> cd19154608610a Stanislav Lisovskiy 2020-05-20  460  			const struct skl_ddb_entry *uv_plane_alloc =
> cd19154608610a Stanislav Lisovskiy 2020-05-20  461  				&crtc_state->wm.skl.plane_ddb_uv[plane_id];
> cd19154608610a Stanislav Lisovskiy 2020-05-20  462  			unsigned int data_rate = crtc_state->data_rate[plane_id];
> cd19154608610a Stanislav Lisovskiy 2020-05-20  463  			unsigned int dbuf_mask = 0;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  464  
> cd19154608610a Stanislav Lisovskiy 2020-05-20  465  			dbuf_mask |= skl_ddb_dbuf_slice_mask(dev_priv, plane_alloc);
> cd19154608610a Stanislav Lisovskiy 2020-05-20  466  			dbuf_mask |= skl_ddb_dbuf_slice_mask(dev_priv, uv_plane_alloc);
> cd19154608610a Stanislav Lisovskiy 2020-05-20  467  
> cd19154608610a Stanislav Lisovskiy 2020-05-20  468  			/*
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  469  			 * FIXME: To calculate that more properly we probably
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  470  			 * need to to split per plane data_rate into data_rate_y
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  471  			 * and data_rate_uv for multiplanar formats in order not
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  472  			 * to get accounted those twice if they happen to reside
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  473  			 * on different slices.
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  474  			 * However for pre-icl this would work anyway because
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  475  			 * we have only single slice and for icl+ uv plane has
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  476  			 * non-zero data rate.
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  477  			 * So in worst case those calculation are a bit
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  478  			 * pessimistic, which shouldn't pose any significant
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  479  			 * problem anyway.
> cd19154608610a Stanislav Lisovskiy 2020-05-20  480  			 */
> cd19154608610a Stanislav Lisovskiy 2020-05-20  481  			for_each_dbuf_slice_in_mask(slice_id, dbuf_mask)
> cd19154608610a Stanislav Lisovskiy 2020-05-20  482  				crtc_bw->used_bw[slice_id] += data_rate;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  483  		}
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  484  	}
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  485  
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  486  	if (!old_bw_state)
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  487  		return 0;
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  488  
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  489  	for_each_pipe(dev_priv, pipe) {
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  490  		struct intel_dbuf_bw *crtc_bw;
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  491  
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  492  		crtc_bw = &new_bw_state->dbuf_bw[pipe];
> cd19154608610a Stanislav Lisovskiy 2020-05-20  493  
> cd19154608610a Stanislav Lisovskiy 2020-05-20  494  		for_each_dbuf_slice(slice_id) {
> cd19154608610a Stanislav Lisovskiy 2020-05-20  495  			/*
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  496  			 * Current experimental observations show that contrary
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  497  			 * to BSpec we get underruns once we exceed 64 * CDCLK
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  498  			 * for slices in total.
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  499  			 * As a temporary measure in order not to keep CDCLK
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  500  			 * bumped up all the time we calculate CDCLK according
> cac91e671ad5dc Stanislav Lisovskiy 2020-05-22  501  			 * to this formula for  overall bw consumed by slices.
> cd19154608610a Stanislav Lisovskiy 2020-05-20  502  			 */
> cd19154608610a Stanislav Lisovskiy 2020-05-20  503  			max_bw += crtc_bw->used_bw[slice_id];
> cd19154608610a Stanislav Lisovskiy 2020-05-20  504  		}
> cd19154608610a Stanislav Lisovskiy 2020-05-20  505  	}
> cd19154608610a Stanislav Lisovskiy 2020-05-20  506  
> 21b0324886122a Stanislav Lisovskiy 2020-05-26  507  	new_bw_state->min_cdclk = max_bw / 64;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  508  
> cd19154608610a Stanislav Lisovskiy 2020-05-20  509  	if (new_bw_state->min_cdclk != old_bw_state->min_cdclk) {
> cd19154608610a Stanislav Lisovskiy 2020-05-20  510  		int ret = intel_atomic_lock_global_state(&new_bw_state->base);
> cd19154608610a Stanislav Lisovskiy 2020-05-20  511  
> cd19154608610a Stanislav Lisovskiy 2020-05-20  512  		if (ret)
> cd19154608610a Stanislav Lisovskiy 2020-05-20  513  			return ret;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  514  	}
> cd19154608610a Stanislav Lisovskiy 2020-05-20  515  
> cd19154608610a Stanislav Lisovskiy 2020-05-20  516  	return 0;
> cd19154608610a Stanislav Lisovskiy 2020-05-20  517  }
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org




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