[v2,14/15] pciutils-pcilmr: Add handling of situations when device reports its MaxOffset values equal to 0

Commit Message

Nikita Proshkin Dec. 27, 2023, 9:45 a.m. UTC

According to spec, for the MaxTimingOffset and MaxVoltageOffset parameters
'A 0 value may be reported if the vendor chooses not to report the offset'.

Use max possible Offset value in such situations and report to the user.

Reviewed-by: Sergei Miroshnichenko <[e-mail]>
Signed-off-by: Nikita Proshkin <[e-mail]>
---
 lmr/lmr.h            |  3 +++
 lmr/margin.c         |  9 +++++++--
 lmr/margin_log.c     |  7 +++++++
 lmr/margin_results.c | 13 +++++++++++++
 4 files changed, 30 insertions(+), 2 deletions(-)

Patch

diff --git a/lmr/lmr.h b/lmr/lmr.h
index c9dcd69..7375c33 100644
--- a/lmr/lmr.h
+++ b/lmr/lmr.h
@@ -107,6 +107,9 @@  struct margin_results {
   double tim_coef;
   double volt_coef;
 
+  bool tim_off_reported;
+  bool volt_off_reported;
+
   u8 lanes_n;
   struct margin_res_lane *lanes;
 };
diff --git a/lmr/margin.c b/lmr/margin.c
index cc142fa..0b14747 100644
--- a/lmr/margin.c
+++ b/lmr/margin.c
@@ -328,8 +328,13 @@  margin_test_receiver(struct margin_dev *dev, u8 recvn, struct margin_args *args,
   margin_apply_hw_quirks(&recv);
   margin_log_hw_quirks(&recv);
 
-  results->tim_coef = (double)params.timing_offset / (double)params.timing_steps;
-  results->volt_coef = (double)params.volt_offset / (double)params.volt_steps * 10.0;
+  results->tim_off_reported = params.timing_offset != 0;
+  results->volt_off_reported = params.volt_offset != 0;
+  double tim_offset = results->tim_off_reported ? (double)params.timing_offset : 50.0;
+  double volt_offset = results->volt_off_reported ? (double)params.volt_offset : 50.0;
+
+  results->tim_coef = tim_offset / (double)params.timing_steps;
+  results->volt_coef = volt_offset / (double)params.volt_steps * 10.0;
 
   results->lane_reversal = recv.lane_reversal;
   results->link_speed = dev->link_speed;
diff --git a/lmr/margin_log.c b/lmr/margin_log.c
index a93e07b..b3c4bd5 100644
--- a/lmr/margin_log.c
+++ b/lmr/margin_log.c
@@ -86,6 +86,13 @@  margin_log_receiver(struct margin_recv *recv)
       margin_log("\nWarning: device uses Lane Reversal.\n");
       margin_log("However, utility uses logical lane numbers in arguments and for logging.\n");
     }
+
+  if (recv->params->timing_offset == 0)
+    margin_log("\nWarning: Vendor chose not to report the Max Timing Offset.\n"
+               "Utility will use its max possible value - 50 (50%% UI).\n");
+  if (recv->params->volt_support && recv->params->volt_offset == 0)
+    margin_log("\nWarning: Vendor chose not to report the Max Voltage Offset.\n"
+               "Utility will use its max possible value - 50 (500 mV).\n");
 }
 
 void
diff --git a/lmr/margin_results.c b/lmr/margin_results.c
index aca3ab7..6d6ed29 100644
--- a/lmr/margin_results.c
+++ b/lmr/margin_results.c
@@ -105,6 +105,19 @@  margin_results_print_brief(struct margin_results *results, u8 recvs_n)
       if (res->lane_reversal)
         printf("Rx(%X) - Lane Reversal\n", 10 + res->recvn - 1);
 
+      if (!res->tim_off_reported)
+        printf("Rx(%X) - Attention: Vendor chose not to report the Max Timing Offset.\n"
+               "Utility used its max possible value (50%% UI) for calculations of %% UI and ps.\n"
+               "Keep in mind that for timing results of this receiver only steps values are "
+               "reliable.\n\n",
+               10 + res->recvn - 1);
+      if (params.volt_support && !res->volt_off_reported)
+        printf("Rx(%X) - Attention: Vendor chose not to report the Max Voltage Offset.\n"
+               "Utility used its max possible value (500 mV) for calculations of mV.\n"
+               "Keep in mind that for voltage results of this receiver only steps values are "
+               "reliable.\n\n",
+               10 + res->recvn - 1);
+
       if (check_recv_weird(res, MARGIN_TIM_MIN, MARGIN_VOLT_MIN))
         lane_rating = WEIRD;
       else