2 * Copyright 2012 Advanced Micro Devices, Inc.
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20 * OTHER DEALINGS IN THE SOFTWARE.
24 #include <linux/pci.h>
25 #include <linux/acpi.h>
26 #include <linux/slab.h>
27 #include <linux/power_supply.h>
28 #include <acpi/video.h>
30 #include <drm/drm_crtc_helper.h>
32 #include "radeon_acpi.h"
35 #define ACPI_AC_CLASS "ac_adapter"
37 extern void radeon_pm_acpi_event_handler(struct radeon_device *rdev);
39 struct atif_verify_interface {
40 u16 size; /* structure size in bytes (includes size field) */
41 u16 version; /* version */
42 u32 notification_mask; /* supported notifications mask */
43 u32 function_bits; /* supported functions bit vector */
46 struct atif_system_params {
47 u16 size; /* structure size in bytes (includes size field) */
48 u32 valid_mask; /* valid flags mask */
49 u32 flags; /* flags */
50 u8 command_code; /* notify command code */
53 struct atif_sbios_requests {
54 u16 size; /* structure size in bytes (includes size field) */
55 u32 pending; /* pending sbios requests */
56 u8 panel_exp_mode; /* panel expansion mode */
57 u8 thermal_gfx; /* thermal state: target gfx controller */
58 u8 thermal_state; /* thermal state: state id (0: exit state, non-0: state) */
59 u8 forced_power_gfx; /* forced power state: target gfx controller */
60 u8 forced_power_state; /* forced power state: state id */
61 u8 system_power_src; /* system power source */
62 u8 backlight_level; /* panel backlight level (0-255) */
65 #define ATIF_NOTIFY_MASK 0x3
66 #define ATIF_NOTIFY_NONE 0
67 #define ATIF_NOTIFY_81 1
68 #define ATIF_NOTIFY_N 2
70 struct atcs_verify_interface {
71 u16 size; /* structure size in bytes (includes size field) */
72 u16 version; /* version */
73 u32 function_bits; /* supported functions bit vector */
76 #define ATCS_VALID_FLAGS_MASK 0x3
78 struct atcs_pref_req_input {
79 u16 size; /* structure size in bytes (includes size field) */
80 u16 client_id; /* client id (bit 2-0: func num, 7-3: dev num, 15-8: bus num) */
81 u16 valid_flags_mask; /* valid flags mask */
82 u16 flags; /* flags */
83 u8 req_type; /* request type */
84 u8 perf_req; /* performance request */
87 struct atcs_pref_req_output {
88 u16 size; /* structure size in bytes (includes size field) */
89 u8 ret_val; /* return value */
92 /* Call the ATIF method
95 * radeon_atif_call - call an ATIF method
97 * @handle: acpi handle
98 * @function: the ATIF function to execute
99 * @params: ATIF function params
101 * Executes the requested ATIF function (all asics).
102 * Returns a pointer to the acpi output buffer.
104 static union acpi_object *radeon_atif_call(acpi_handle handle, int function,
105 struct acpi_buffer *params)
108 union acpi_object atif_arg_elements[2];
109 struct acpi_object_list atif_arg;
110 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
113 atif_arg.pointer = &atif_arg_elements[0];
115 atif_arg_elements[0].type = ACPI_TYPE_INTEGER;
116 atif_arg_elements[0].integer.value = function;
119 atif_arg_elements[1].type = ACPI_TYPE_BUFFER;
120 atif_arg_elements[1].buffer.length = params->length;
121 atif_arg_elements[1].buffer.pointer = params->pointer;
123 /* We need a second fake parameter */
124 atif_arg_elements[1].type = ACPI_TYPE_INTEGER;
125 atif_arg_elements[1].integer.value = 0;
128 status = acpi_evaluate_object(handle, "ATIF", &atif_arg, &buffer);
130 /* Fail only if calling the method fails and ATIF is supported */
131 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
132 DRM_DEBUG_DRIVER("failed to evaluate ATIF got %s\n",
133 acpi_format_exception(status));
134 kfree(buffer.pointer);
138 return buffer.pointer;
142 * radeon_atif_parse_notification - parse supported notifications
144 * @n: supported notifications struct
145 * @mask: supported notifications mask from ATIF
147 * Use the supported notifications mask from ATIF function
148 * ATIF_FUNCTION_VERIFY_INTERFACE to determine what notifications
149 * are supported (all asics).
151 static void radeon_atif_parse_notification(struct radeon_atif_notifications *n, u32 mask)
153 n->display_switch = mask & ATIF_DISPLAY_SWITCH_REQUEST_SUPPORTED;
154 n->expansion_mode_change = mask & ATIF_EXPANSION_MODE_CHANGE_REQUEST_SUPPORTED;
155 n->thermal_state = mask & ATIF_THERMAL_STATE_CHANGE_REQUEST_SUPPORTED;
156 n->forced_power_state = mask & ATIF_FORCED_POWER_STATE_CHANGE_REQUEST_SUPPORTED;
157 n->system_power_state = mask & ATIF_SYSTEM_POWER_SOURCE_CHANGE_REQUEST_SUPPORTED;
158 n->display_conf_change = mask & ATIF_DISPLAY_CONF_CHANGE_REQUEST_SUPPORTED;
159 n->px_gfx_switch = mask & ATIF_PX_GFX_SWITCH_REQUEST_SUPPORTED;
160 n->brightness_change = mask & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST_SUPPORTED;
161 n->dgpu_display_event = mask & ATIF_DGPU_DISPLAY_EVENT_SUPPORTED;
165 * radeon_atif_parse_functions - parse supported functions
167 * @f: supported functions struct
168 * @mask: supported functions mask from ATIF
170 * Use the supported functions mask from ATIF function
171 * ATIF_FUNCTION_VERIFY_INTERFACE to determine what functions
172 * are supported (all asics).
174 static void radeon_atif_parse_functions(struct radeon_atif_functions *f, u32 mask)
176 f->system_params = mask & ATIF_GET_SYSTEM_PARAMETERS_SUPPORTED;
177 f->sbios_requests = mask & ATIF_GET_SYSTEM_BIOS_REQUESTS_SUPPORTED;
178 f->select_active_disp = mask & ATIF_SELECT_ACTIVE_DISPLAYS_SUPPORTED;
179 f->lid_state = mask & ATIF_GET_LID_STATE_SUPPORTED;
180 f->get_tv_standard = mask & ATIF_GET_TV_STANDARD_FROM_CMOS_SUPPORTED;
181 f->set_tv_standard = mask & ATIF_SET_TV_STANDARD_IN_CMOS_SUPPORTED;
182 f->get_panel_expansion_mode = mask & ATIF_GET_PANEL_EXPANSION_MODE_FROM_CMOS_SUPPORTED;
183 f->set_panel_expansion_mode = mask & ATIF_SET_PANEL_EXPANSION_MODE_IN_CMOS_SUPPORTED;
184 f->temperature_change = mask & ATIF_TEMPERATURE_CHANGE_NOTIFICATION_SUPPORTED;
185 f->graphics_device_types = mask & ATIF_GET_GRAPHICS_DEVICE_TYPES_SUPPORTED;
189 * radeon_atif_verify_interface - verify ATIF
191 * @handle: acpi handle
192 * @atif: radeon atif struct
194 * Execute the ATIF_FUNCTION_VERIFY_INTERFACE ATIF function
195 * to initialize ATIF and determine what features are supported
197 * returns 0 on success, error on failure.
199 static int radeon_atif_verify_interface(acpi_handle handle,
200 struct radeon_atif *atif)
202 union acpi_object *info;
203 struct atif_verify_interface output;
207 info = radeon_atif_call(handle, ATIF_FUNCTION_VERIFY_INTERFACE, NULL);
211 memset(&output, 0, sizeof(output));
213 size = *(u16 *) info->buffer.pointer;
215 DRM_INFO("ATIF buffer is too small: %zu\n", size);
219 size = min(sizeof(output), size);
221 memcpy(&output, info->buffer.pointer, size);
223 /* TODO: check version? */
224 DRM_DEBUG_DRIVER("ATIF version %u\n", output.version);
226 radeon_atif_parse_notification(&atif->notifications, output.notification_mask);
227 radeon_atif_parse_functions(&atif->functions, output.function_bits);
235 * radeon_atif_get_notification_params - determine notify configuration
237 * @handle: acpi handle
238 * @n: atif notification configuration struct
240 * Execute the ATIF_FUNCTION_GET_SYSTEM_PARAMETERS ATIF function
241 * to determine if a notifier is used and if so which one
242 * (all asics). This is either Notify(VGA, 0x81) or Notify(VGA, n)
243 * where n is specified in the result if a notifier is used.
244 * Returns 0 on success, error on failure.
246 static int radeon_atif_get_notification_params(acpi_handle handle,
247 struct radeon_atif_notification_cfg *n)
249 union acpi_object *info;
250 struct atif_system_params params;
254 info = radeon_atif_call(handle, ATIF_FUNCTION_GET_SYSTEM_PARAMETERS, NULL);
260 size = *(u16 *) info->buffer.pointer;
266 memset(¶ms, 0, sizeof(params));
267 size = min(sizeof(params), size);
268 memcpy(¶ms, info->buffer.pointer, size);
270 DRM_DEBUG_DRIVER("SYSTEM_PARAMS: mask = %#x, flags = %#x\n",
271 params.flags, params.valid_mask);
272 params.flags = params.flags & params.valid_mask;
274 if ((params.flags & ATIF_NOTIFY_MASK) == ATIF_NOTIFY_NONE) {
277 } else if ((params.flags & ATIF_NOTIFY_MASK) == ATIF_NOTIFY_81) {
279 n->command_code = 0x81;
286 n->command_code = params.command_code;
290 DRM_DEBUG_DRIVER("Notification %s, command code = %#x\n",
291 (n->enabled ? "enabled" : "disabled"),
298 * radeon_atif_get_sbios_requests - get requested sbios event
300 * @handle: acpi handle
301 * @req: atif sbios request struct
303 * Execute the ATIF_FUNCTION_GET_SYSTEM_BIOS_REQUESTS ATIF function
304 * to determine what requests the sbios is making to the driver
306 * Returns 0 on success, error on failure.
308 static int radeon_atif_get_sbios_requests(acpi_handle handle,
309 struct atif_sbios_requests *req)
311 union acpi_object *info;
315 info = radeon_atif_call(handle, ATIF_FUNCTION_GET_SYSTEM_BIOS_REQUESTS, NULL);
319 size = *(u16 *)info->buffer.pointer;
324 memset(req, 0, sizeof(*req));
326 size = min(sizeof(*req), size);
327 memcpy(req, info->buffer.pointer, size);
328 DRM_DEBUG_DRIVER("SBIOS pending requests: %#x\n", req->pending);
330 count = hweight32(req->pending);
338 * radeon_atif_handler - handle ATIF notify requests
340 * @rdev: radeon_device pointer
341 * @event: atif sbios request struct
343 * Checks the acpi event and if it matches an atif event,
345 * Returns NOTIFY code
347 int radeon_atif_handler(struct radeon_device *rdev,
348 struct acpi_bus_event *event)
350 struct radeon_atif *atif = &rdev->atif;
351 struct atif_sbios_requests req;
355 DRM_DEBUG_DRIVER("event, device_class = %s, type = %#x\n",
356 event->device_class, event->type);
358 if (strcmp(event->device_class, ACPI_VIDEO_CLASS) != 0)
361 if (!atif->notification_cfg.enabled ||
362 event->type != atif->notification_cfg.command_code)
366 /* Check pending SBIOS requests */
367 handle = ACPI_HANDLE(&rdev->pdev->dev);
368 count = radeon_atif_get_sbios_requests(handle, &req);
373 DRM_DEBUG_DRIVER("ATIF: %d pending SBIOS requests\n", count);
375 if (req.pending & ATIF_PANEL_BRIGHTNESS_CHANGE_REQUEST) {
376 struct radeon_encoder *enc = atif->encoder_for_bl;
379 DRM_DEBUG_DRIVER("Changing brightness to %d\n",
380 req.backlight_level);
382 radeon_set_backlight_level(rdev, enc, req.backlight_level);
384 #if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
385 if (rdev->is_atom_bios) {
386 struct radeon_encoder_atom_dig *dig = enc->enc_priv;
387 backlight_force_update(dig->bl_dev,
388 BACKLIGHT_UPDATE_HOTKEY);
390 struct radeon_encoder_lvds *dig = enc->enc_priv;
391 backlight_force_update(dig->bl_dev,
392 BACKLIGHT_UPDATE_HOTKEY);
397 /* TODO: check other events */
399 /* We've handled the event, stop the notifier chain. The ACPI interface
400 * overloads ACPI_VIDEO_NOTIFY_PROBE, we don't want to send that to
401 * userspace if the event was generated only to signal a SBIOS
407 /* Call the ATCS method
410 * radeon_atcs_call - call an ATCS method
412 * @handle: acpi handle
413 * @function: the ATCS function to execute
414 * @params: ATCS function params
416 * Executes the requested ATCS function (all asics).
417 * Returns a pointer to the acpi output buffer.
419 static union acpi_object *radeon_atcs_call(acpi_handle handle, int function,
420 struct acpi_buffer *params)
423 union acpi_object atcs_arg_elements[2];
424 struct acpi_object_list atcs_arg;
425 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
428 atcs_arg.pointer = &atcs_arg_elements[0];
430 atcs_arg_elements[0].type = ACPI_TYPE_INTEGER;
431 atcs_arg_elements[0].integer.value = function;
434 atcs_arg_elements[1].type = ACPI_TYPE_BUFFER;
435 atcs_arg_elements[1].buffer.length = params->length;
436 atcs_arg_elements[1].buffer.pointer = params->pointer;
438 /* We need a second fake parameter */
439 atcs_arg_elements[1].type = ACPI_TYPE_INTEGER;
440 atcs_arg_elements[1].integer.value = 0;
443 status = acpi_evaluate_object(handle, "ATCS", &atcs_arg, &buffer);
445 /* Fail only if calling the method fails and ATIF is supported */
446 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
447 DRM_DEBUG_DRIVER("failed to evaluate ATCS got %s\n",
448 acpi_format_exception(status));
449 kfree(buffer.pointer);
453 return buffer.pointer;
457 * radeon_atcs_parse_functions - parse supported functions
459 * @f: supported functions struct
460 * @mask: supported functions mask from ATCS
462 * Use the supported functions mask from ATCS function
463 * ATCS_FUNCTION_VERIFY_INTERFACE to determine what functions
464 * are supported (all asics).
466 static void radeon_atcs_parse_functions(struct radeon_atcs_functions *f, u32 mask)
468 f->get_ext_state = mask & ATCS_GET_EXTERNAL_STATE_SUPPORTED;
469 f->pcie_perf_req = mask & ATCS_PCIE_PERFORMANCE_REQUEST_SUPPORTED;
470 f->pcie_dev_rdy = mask & ATCS_PCIE_DEVICE_READY_NOTIFICATION_SUPPORTED;
471 f->pcie_bus_width = mask & ATCS_SET_PCIE_BUS_WIDTH_SUPPORTED;
475 * radeon_atcs_verify_interface - verify ATCS
477 * @handle: acpi handle
478 * @atcs: radeon atcs struct
480 * Execute the ATCS_FUNCTION_VERIFY_INTERFACE ATCS function
481 * to initialize ATCS and determine what features are supported
483 * returns 0 on success, error on failure.
485 static int radeon_atcs_verify_interface(acpi_handle handle,
486 struct radeon_atcs *atcs)
488 union acpi_object *info;
489 struct atcs_verify_interface output;
493 info = radeon_atcs_call(handle, ATCS_FUNCTION_VERIFY_INTERFACE, NULL);
497 memset(&output, 0, sizeof(output));
499 size = *(u16 *) info->buffer.pointer;
501 DRM_INFO("ATCS buffer is too small: %zu\n", size);
505 size = min(sizeof(output), size);
507 memcpy(&output, info->buffer.pointer, size);
509 /* TODO: check version? */
510 DRM_DEBUG_DRIVER("ATCS version %u\n", output.version);
512 radeon_atcs_parse_functions(&atcs->functions, output.function_bits);
520 * radeon_acpi_is_pcie_performance_request_supported
522 * @rdev: radeon_device pointer
524 * Check if the ATCS pcie_perf_req and pcie_dev_rdy methods
525 * are supported (all asics).
526 * returns true if supported, false if not.
528 bool radeon_acpi_is_pcie_performance_request_supported(struct radeon_device *rdev)
530 struct radeon_atcs *atcs = &rdev->atcs;
532 if (atcs->functions.pcie_perf_req && atcs->functions.pcie_dev_rdy)
539 * radeon_acpi_pcie_notify_device_ready
541 * @rdev: radeon_device pointer
543 * Executes the PCIE_DEVICE_READY_NOTIFICATION method
545 * returns 0 on success, error on failure.
547 int radeon_acpi_pcie_notify_device_ready(struct radeon_device *rdev)
550 union acpi_object *info;
551 struct radeon_atcs *atcs = &rdev->atcs;
553 /* Get the device handle */
554 handle = ACPI_HANDLE(&rdev->pdev->dev);
558 if (!atcs->functions.pcie_dev_rdy)
561 info = radeon_atcs_call(handle, ATCS_FUNCTION_PCIE_DEVICE_READY_NOTIFICATION, NULL);
571 * radeon_acpi_pcie_performance_request
573 * @rdev: radeon_device pointer
574 * @perf_req: requested perf level (pcie gen speed)
575 * @advertise: set advertise caps flag if set
577 * Executes the PCIE_PERFORMANCE_REQUEST method to
578 * change the pcie gen speed (all asics).
579 * returns 0 on success, error on failure.
581 int radeon_acpi_pcie_performance_request(struct radeon_device *rdev,
582 u8 perf_req, bool advertise)
585 union acpi_object *info;
586 struct radeon_atcs *atcs = &rdev->atcs;
587 struct atcs_pref_req_input atcs_input;
588 struct atcs_pref_req_output atcs_output;
589 struct acpi_buffer params;
593 /* Get the device handle */
594 handle = ACPI_HANDLE(&rdev->pdev->dev);
598 if (!atcs->functions.pcie_perf_req)
601 atcs_input.size = sizeof(struct atcs_pref_req_input);
602 /* client id (bit 2-0: func num, 7-3: dev num, 15-8: bus num) */
603 atcs_input.client_id = rdev->pdev->devfn | (rdev->pdev->bus->number << 8);
604 atcs_input.valid_flags_mask = ATCS_VALID_FLAGS_MASK;
605 atcs_input.flags = ATCS_WAIT_FOR_COMPLETION;
607 atcs_input.flags |= ATCS_ADVERTISE_CAPS;
608 atcs_input.req_type = ATCS_PCIE_LINK_SPEED;
609 atcs_input.perf_req = perf_req;
611 params.length = sizeof(struct atcs_pref_req_input);
612 params.pointer = &atcs_input;
615 info = radeon_atcs_call(handle, ATCS_FUNCTION_PCIE_PERFORMANCE_REQUEST, ¶ms);
619 memset(&atcs_output, 0, sizeof(atcs_output));
621 size = *(u16 *) info->buffer.pointer;
623 DRM_INFO("ATCS buffer is too small: %zu\n", size);
627 size = min(sizeof(atcs_output), size);
629 memcpy(&atcs_output, info->buffer.pointer, size);
633 switch (atcs_output.ret_val) {
634 case ATCS_REQUEST_REFUSED:
637 case ATCS_REQUEST_COMPLETE:
639 case ATCS_REQUEST_IN_PROGRESS:
649 * radeon_acpi_event - handle notify events
651 * @nb: notifier block
655 * Calls relevant radeon functions in response to various
657 * Returns NOTIFY code
659 static int radeon_acpi_event(struct notifier_block *nb,
663 struct radeon_device *rdev = container_of(nb, struct radeon_device, acpi_nb);
664 struct acpi_bus_event *entry = (struct acpi_bus_event *)data;
666 if (strcmp(entry->device_class, ACPI_AC_CLASS) == 0) {
667 if (power_supply_is_system_supplied() > 0)
668 DRM_DEBUG_DRIVER("pm: AC\n");
670 DRM_DEBUG_DRIVER("pm: DC\n");
672 radeon_pm_acpi_event_handler(rdev);
675 /* Check for pending SBIOS requests */
676 return radeon_atif_handler(rdev, entry);
679 /* Call all ACPI methods here */
681 * radeon_acpi_init - init driver acpi support
683 * @rdev: radeon_device pointer
685 * Verifies the AMD ACPI interfaces and registers with the acpi
686 * notifier chain (all asics).
687 * Returns 0 on success, error on failure.
689 int radeon_acpi_init(struct radeon_device *rdev)
692 struct radeon_atif *atif = &rdev->atif;
693 struct radeon_atcs *atcs = &rdev->atcs;
696 /* Get the device handle */
697 handle = ACPI_HANDLE(&rdev->pdev->dev);
699 /* No need to proceed if we're sure that ATIF is not supported */
700 if (!ASIC_IS_AVIVO(rdev) || !rdev->bios || !handle)
703 /* Call the ATCS method */
704 ret = radeon_atcs_verify_interface(handle, atcs);
706 DRM_DEBUG_DRIVER("Call to ATCS verify_interface failed: %d\n", ret);
709 /* Call the ATIF method */
710 ret = radeon_atif_verify_interface(handle, atif);
712 DRM_DEBUG_DRIVER("Call to ATIF verify_interface failed: %d\n", ret);
716 if (atif->notifications.brightness_change) {
717 struct drm_encoder *tmp;
718 struct radeon_encoder *target = NULL;
720 /* Find the encoder controlling the brightness */
721 list_for_each_entry(tmp, &rdev->ddev->mode_config.encoder_list,
723 struct radeon_encoder *enc = to_radeon_encoder(tmp);
725 if ((enc->devices & (ATOM_DEVICE_LCD_SUPPORT)) &&
727 if (rdev->is_atom_bios) {
728 struct radeon_encoder_atom_dig *dig = enc->enc_priv;
734 struct radeon_encoder_lvds *dig = enc->enc_priv;
743 atif->encoder_for_bl = target;
745 /* Brightness change notification is enabled, but we
746 * didn't find a backlight controller, this should
749 DRM_ERROR("Cannot find a backlight controller\n");
753 if (atif->functions.sbios_requests && !atif->functions.system_params) {
754 /* XXX check this workraround, if sbios request function is
755 * present we have to see how it's configured in the system
758 atif->functions.system_params = true;
761 if (atif->functions.system_params) {
762 ret = radeon_atif_get_notification_params(handle,
763 &atif->notification_cfg);
765 DRM_DEBUG_DRIVER("Call to GET_SYSTEM_PARAMS failed: %d\n",
767 /* Disable notification */
768 atif->notification_cfg.enabled = false;
773 rdev->acpi_nb.notifier_call = radeon_acpi_event;
774 register_acpi_notifier(&rdev->acpi_nb);
780 * radeon_acpi_fini - tear down driver acpi support
782 * @rdev: radeon_device pointer
784 * Unregisters with the acpi notifier chain (all asics).
786 void radeon_acpi_fini(struct radeon_device *rdev)
788 unregister_acpi_notifier(&rdev->acpi_nb);