hidpp10: pass the dpi list to libratbag as-is

If our device only has a discrete number of DPIs, pass it on as-is to
libratbag rather than pretending it's a range and then failing to set the
DPIs.

For the actual ranged devices we use libratbag's now-exponential range
mapping rather than passing all possible ones on. This relies on us having the
same steps that libratbag uses, should be safe enough.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

src/driver-hidpp10.c

@@ -417,7 +417,7 @@ hidpp10drv_read_profile(struct ratbag_profile *profile)
 	ratbag_device_set_capability(device, RATBAG_DEVICE_CAP_SWITCHABLE_RESOLUTION);
 
 	ratbag_profile_for_each_resolution(profile, res) {
-		unsigned int min, max;
+		unsigned int dpis[hidpp10->dpi_count];
 
 		ratbag_resolution_set_resolution(res,
 						 p.dpi_modes[res->index].xres,
@@ -435,9 +435,20 @@ hidpp10drv_read_profile(struct ratbag_profile *profile)
 				res->is_active = true;
 		}
 
-		min = hidpp10_dpi_table_get_min_dpi(hidpp10);
-		max = hidpp10_dpi_table_get_max_dpi(hidpp10);
-		ratbag_resolution_set_dpi_list_from_range(res, min, max);
+		if (hidpp10->dpi_table_is_range) {
+			unsigned int min, max;
+
+			min = hidpp10_dpi_table_get_min_dpi(hidpp10);
+			max = hidpp10_dpi_table_get_max_dpi(hidpp10);
+			/* FIXME: this relies on libratbag using the
+			 * same steps that we support */
+			ratbag_resolution_set_dpi_list_from_range(res, min, max);
+		} else {
+			for (int i = 0; i < hidpp10->dpi_count - 1; i++)
+				dpis[i] = hidpp10->dpi_table[i].dpi;
+
+			ratbag_resolution_set_dpi_list(res, dpis, hidpp10->dpi_count);
+		}
 	}
 
 	ratbag_profile_for_each_button(profile, button)

src/hidpp10.c

@@ -123,6 +123,7 @@ hidpp10_build_dpi_table_from_list(struct hidpp10_device *dev,
 
 	dev->dpi_count = list->nentries;
 	dev->dpi_table = zalloc(list->nentries * sizeof(*dev->dpi_table));
+	dev->dpi_table_is_range = false;
 
 	for (i = 0; i < list->nentries; i++) {
 		dev->dpi_table[i].raw_value = i + 0x80;
@@ -150,6 +151,7 @@ hidpp10_build_dpi_table_from_dpi_info(struct hidpp10_device *dev,
 
 	dev->dpi_count = raw_max + 1;
 	dev->dpi_table = zalloc((raw_max + 1) * sizeof(*dev->dpi_table));
+	dev->dpi_table_is_range = true;
 
 	for (i = 1; i <= raw_max; i++) {
 		dev->dpi_table[i].raw_value = i;

src/hidpp10.h

@@ -60,6 +60,8 @@ struct hidpp10_dpi_mapping {
 struct hidpp10_device  {
 	struct hidpp_device base;
 	unsigned index;
+
+	bool dpi_table_is_range;
 	uint8_t dpi_count;
 	struct hidpp10_dpi_mapping *dpi_table;
 	enum hidpp10_profile_type profile_type;

src/libratbag-private.h

@@ -511,6 +511,21 @@ ratbag_resolution_set_dpi_list_from_range(struct ratbag_resolution *res,
 				  res->profile->device->name);
 }
 
+static inline void
+ratbag_resolution_set_dpi_list(struct ratbag_resolution *res,
+			       unsigned int *dpis,
+			       size_t ndpis)
+{
+	assert(ndpis <= ARRAY_LENGTH(res->dpis));
+	_Static_assert(sizeof(*dpis) == sizeof(*res->dpis), "Mismatching size");
+
+	for (size_t i = 0; i < ndpis; i++) {
+		res->dpis[i] = dpis[i];
+		if (i > 0)
+			assert(dpis[i] > dpis[i - 1]);
+	}
+}
+
 static inline void
 ratbag_resolution_set_cap(struct ratbag_resolution *res,
 			  enum ratbag_resolution_capability cap)