genesys: Fix step multiplier handling in motor table manipulation utils

backend/genesys/gl646.cpp

@@ -649,10 +649,10 @@ void CommandSetGl646::init_regs_for_scan_session(Genesys_Device* dev, const Gene
     // a proper backtracking curve. We're using slightly lower limit to allow at least a minimum
     // distance between accelerations (forward_steps, backward_steps)
     if (slope_table1.table.size() > slope_table2.table.size() + 100) {
-        slope_table2.expand_table(slope_table1.table.size() - 100);
+        slope_table2.expand_table(slope_table1.table.size() - 100, 1);
     }
     if (slope_table2.table.size() > slope_table1.table.size() + 100) {
-        slope_table1.expand_table(slope_table2.table.size() - 100);
+        slope_table1.expand_table(slope_table2.table.size() - 100, 1);
     }
 
     if (slope_table1.table.size() >= slope_table2.table.size()) {

backend/genesys/gl841.cpp

@@ -681,14 +681,14 @@ static void gl841_init_motor_regs_scan(Genesys_Device* dev, const Genesys_Sensor
     auto fast_table = create_slope_table_fastest(dev->model->asic_type, step_multiplier,
                                                  *fast_profile);
 
-    unsigned max_fast_slope_steps_count = 1;
+    unsigned max_fast_slope_steps_count = step_multiplier;
     if (feed_steps > (slow_table.table.size() >> static_cast<unsigned>(motor_profile.step_type)) + 2) {
         max_fast_slope_steps_count = (feed_steps -
             (slow_table.table.size() >> static_cast<unsigned>(motor_profile.step_type))) / 2;
     }
 
     if (fast_table.table.size() > max_fast_slope_steps_count) {
-        fast_table.slice_steps(max_fast_slope_steps_count);
+        fast_table.slice_steps(max_fast_slope_steps_count, step_multiplier);
     }
 
     /* fast fed special cases handling */

backend/genesys/motor.cpp

@@ -43,6 +43,7 @@
 
 #define DEBUG_DECLARE_ONLY
 
+#include "low.h"
 #include "motor.h"
 #include "utilities.h"
 #include <cmath>
@@ -81,20 +82,22 @@ MotorSlope MotorSlope::create_from_steps(unsigned initial_w, unsigned max_w,
     return slope;
 }
 
-void MotorSlopeTable::slice_steps(unsigned count)
+void MotorSlopeTable::slice_steps(unsigned count, unsigned step_multiplier)
 {
-    if (count > table.size()) {
-        throw SaneException("Excessive steps count");
+    if (count > table.size() || count < step_multiplier) {
+        throw SaneException("Invalid steps count");
     }
+    count = align_multiple_floor(count, step_multiplier);
     table.resize(count);
     generate_pixeltime_sum();
 }
 
-void MotorSlopeTable::expand_table(unsigned count)
+void MotorSlopeTable::expand_table(unsigned count, unsigned step_multiplier)
 {
     if (table.empty()) {
         throw SaneException("Can't expand empty table");
     }
+    count = align_multiple_ceil(count, step_multiplier);
     table.resize(table.size() + count, table.back());
     generate_pixeltime_sum();
 }

backend/genesys/motor.h

@@ -127,10 +127,10 @@ struct MotorSlopeTable
 {
     std::vector<std::uint16_t> table;
 
-    void slice_steps(unsigned count);
+    void slice_steps(unsigned count, unsigned step_multiplier);
 
     // expands the table by the given number of steps
-    void expand_table(unsigned count);
+    void expand_table(unsigned count, unsigned step_multiplier);
 
     std::uint64_t pixeltime_sum() const { return pixeltime_sum_; }