Re: [PATCH] drm/msm/dpu: add DSC range checking during resource reservation

[Dmitry Baryshkov]

On 12/04/2023 00:09, Kuogee Hsieh wrote:
Perform DSC range checking to make sure correct DSC is requested before
reserve resource for it.
Fixes: c985d7bb64ff ("drm/msm/disp/dpu1: Add DSC support in RM")

$ git log -p -1 c985d7bb64ff
fatal: ambiguous argument 'c985d7bb64ff': unknown revision or path not 
in the working tree.

I assume this was generated against some internal tree. Please. Please. 
Don't do this again. I hoped that this was pointed out ages ago, but 
probably not. No fixes, commits, tests against internal trees, no matter 
how precious they are to you.

Signed-off-by: Kuogee Hsieh <quic_khs...@quicinc.com>
---
  drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c | 10 +++++++++-
  1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c 
b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
index f4dda88..95e58f1 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
@@ -1,6 +1,7 @@
  // SPDX-License-Identifier: GPL-2.0-only
  /*
   * Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
   */
  
  #define pr_fmt(fmt)	"[drm:%s] " fmt, __func__
@@ -250,6 +251,11 @@ int dpu_rm_init(struct dpu_rm *rm,
                struct dpu_hw_dsc *hw;
                const struct dpu_dsc_cfg *dsc = &cat->dsc[i];
  
+		if (dsc->id < DSC_0 || dsc->id >= DSC_MAX) {
+                       DPU_ERROR("skip dsc %d with invalid id\n", dsc->id);
+                       continue;
+               }
+
                hw = dpu_hw_dsc_init(dsc->id, mmio, cat);
                if (IS_ERR_OR_NULL(hw)) {
                        rc = PTR_ERR(hw);
@@ -557,8 +563,10 @@ static int _dpu_rm_make_reservation(
        }
  
  	ret  = _dpu_rm_reserve_dsc(rm, global_state, enc, &reqs->topology);
-       if (ret)
+       if (ret) {
+               DPU_ERROR("unable to find appropriate DSC\n");
                return ret;
+       }
  
  	return ret;
  }

--
With best wishes
Dmitry