Sadly I too am looking for some guidance on getting this modified driver to compile in 15.04, though the list of errors has grown substantially. Trying to install the raring toshiba-acpi-fix from @keks9n's PPA results in some pretty scary messages:

Building toshiba_acpi for 3.19.0-23-generic
make -C /lib/modules/3.19.0-23-generic/build M=/tmp/tmp.85ijquWhNN modules
make[1]: Entering directory '/usr/src/linux-headers-3.19.0-23-generic'
  CC [M]  /tmp/tmp.85ijquWhNN/toshiba_acpi.o
In file included from /tmp/tmp.85ijquWhNN/toshiba_acpi.c:74:0:
include/acpi/acpi_drivers.h:86:32: error: unknown type name ‘acpi_handle’
 int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
                                ^
include/acpi/acpi_drivers.h:88:28: error: unknown type name ‘acpi_handle’
 int acpi_pci_link_free_irq(acpi_handle handle);
                            ^
include/acpi/acpi_drivers.h:94:8: warning: parameter names (without types) in function declaration
 struct pci_dev *acpi_get_pci_dev(acpi_handle);
        ^
include/acpi/acpi_drivers.h:98:43: warning: ‘struct acpi_pci_root’ declared inside parameter list
 struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root);
                                           ^
include/acpi/acpi_drivers.h:98:43: warning: its scope is only this definition or declaration, which is probably not what you want
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘is_valid_acpi_path’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:180:2: error: unknown type name ‘acpi_handle’
  acpi_handle handle;
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:181:2: error: unknown type name ‘acpi_status’
  acpi_status status;
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:183:2: error: implicit declaration of function ‘acpi_get_handle’ [-Werror=implicit-function-declaration]
  status = acpi_get_handle(NULL, (char *)methodName, &handle);
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:184:2: error: implicit declaration of function ‘ACPI_FAILURE’ [-Werror=implicit-function-declaration]
  return !ACPI_FAILURE(status);
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘write_acpi_int’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:189:26: error: storage size of ‘params’ isn’t known
  struct acpi_object_list params;
                          ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:190:20: error: array type has incomplete element type
  union acpi_object in_objs[1];
                    ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:191:2: error: unknown type name ‘acpi_status’
  acpi_status status;
  ^
In file included from include/linux/thread_info.h:11:0,
                 from ./arch/x86/include/asm/preempt.h:6,
                 from include/linux/preempt.h:18,
                 from include/linux/spinlock.h:50,
                 from include/linux/seqlock.h:35,
                 from include/linux/time.h:5,
                 from include/linux/stat.h:18,
                 from include/linux/module.h:10,
                 from /tmp/tmp.85ijquWhNN/toshiba_acpi.c:57:
include/linux/bug.h:33:45: error: bit-field ‘<anonymous>’ width not an integer constant
 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
                                             ^
include/linux/compiler-gcc.h:47:28: note: in expansion of macro ‘BUILD_BUG_ON_ZERO’
 #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                            ^
include/linux/kernel.h:54:59: note: in expansion of macro ‘__must_be_array’
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                           ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:193:17: note: in expansion of macro ‘ARRAY_SIZE’
  params.count = ARRAY_SIZE(in_objs);
                 ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:195:20: error: ‘ACPI_TYPE_INTEGER’ undeclared (first use in this function)
  in_objs[0].type = ACPI_TYPE_INTEGER;
                    ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:195:20: note: each undeclared identifier is reported only once for each function it appears in
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:198:2: error: implicit declaration of function ‘acpi_evaluate_object’ [-Werror=implicit-function-declaration]
  status = acpi_evaluate_object(NULL, (char *)methodName, &params, NULL);
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:199:20: error: ‘AE_OK’ undeclared (first use in this function)
  return (status == AE_OK);
                    ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:190:20: warning: unused variable ‘in_objs’ [-Wunused-variable]
  union acpi_object in_objs[1];
                    ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:189:26: warning: unused variable ‘params’ [-Wunused-variable]
  struct acpi_object_list params;
                          ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: At top level:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:224:8: error: unknown type name ‘acpi_status’
 static acpi_status hci_raw(const u32 in[HCI_WORDS], u32 out[HCI_WORDS])
        ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘hci_raw’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:226:26: error: storage size of ‘params’ isn’t known
  struct acpi_object_list params;
                          ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:227:20: error: array type has incomplete element type
  union acpi_object in_objs[HCI_WORDS];
                    ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:228:21: error: storage size of ‘results’ isn’t known
  struct acpi_buffer results;
                     ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:229:20: error: array type has incomplete element type
  union acpi_object out_objs[HCI_WORDS + 1];
                    ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:230:2: error: unknown type name ‘acpi_status’
  acpi_status status;
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:236:21: error: ‘ACPI_TYPE_INTEGER’ undeclared (first use in this function)
   in_objs[i].type = ACPI_TYPE_INTEGER;
                     ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:245:17: error: ‘AE_OK’ undeclared (first use in this function)
  if ((status == AE_OK) && (out_objs->package.count <= HCI_WORDS)) {
                 ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:229:20: warning: unused variable ‘out_objs’ [-Wunused-variable]
  union acpi_object out_objs[HCI_WORDS + 1];
                    ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:228:21: warning: unused variable ‘results’ [-Wunused-variable]
  struct acpi_buffer results;
                     ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:227:20: warning: unused variable ‘in_objs’ [-Wunused-variable]
  union acpi_object in_objs[HCI_WORDS];
                    ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:226:26: warning: unused variable ‘params’ [-Wunused-variable]
  struct acpi_object_list params;
                          ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: At top level:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:260:8: error: unknown type name ‘acpi_status’
 static acpi_status hci_write1(u32 reg, u32 in1, u32 * result)
        ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘hci_write1’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:264:2: error: unknown type name ‘acpi_status’
  acpi_status status = hci_raw(in, out);
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:265:23: error: ‘AE_OK’ undeclared (first use in this function)
  *result = (status == AE_OK) ? out[0] : HCI_FAILURE;
                       ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: At top level:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:269:8: error: unknown type name ‘acpi_status’
 static acpi_status hci_read1(u32 reg, u32 * out1, u32 * result)
        ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘hci_read1’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:273:2: error: unknown type name ‘acpi_status’
  acpi_status status = hci_raw(in, out);
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:275:23: error: ‘AE_OK’ undeclared (first use in this function)
  *result = (status == AE_OK) ? out[0] : HCI_FAILURE;
                       ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: At top level:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:279:8: error: unknown type name ‘acpi_status’
 static acpi_status hci_write2(u32 reg, u32 in1, u32 in2, u32 *result)
        ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘hci_write2’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:283:2: error: unknown type name ‘acpi_status’
  acpi_status status = hci_raw(in, out);
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:284:23: error: ‘AE_OK’ undeclared (first use in this function)
  *result = (status == AE_OK) ? out[0] : HCI_FAILURE;
                       ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: At top level:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:288:8: error: unknown type name ‘acpi_status’
 static acpi_status hci_read2(u32 reg, u32 *out1, u32 *out2, u32 *result)
        ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘hci_read2’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:292:2: error: unknown type name ‘acpi_status’
  acpi_status status = hci_raw(in, out);
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:295:23: error: ‘AE_OK’ undeclared (first use in this function)
  *result = (status == AE_OK) ? out[0] : HCI_FAILURE;
                       ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: At top level:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:304:2: error: unknown type name ‘acpi_handle’
  acpi_handle handle;
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘toshiba_illumination_available’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:316:2: error: unknown type name ‘acpi_status’
  acpi_status status;
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘toshiba_illumination_set’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:334:2: error: unknown type name ‘acpi_status’
  acpi_status status;
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘toshiba_illumination_get’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:377:2: error: unknown type name ‘acpi_status’
  acpi_status status;
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘version_proc_open’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:827:2: error: implicit declaration of function ‘PDE’ [-Werror=implicit-function-declaration]
  return single_open(file, version_proc_show, PDE(inode)->data);
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:827:56: error: invalid type argument of ‘->’ (have ‘int’)
  return single_open(file, version_proc_show, PDE(inode)->data);
                                                        ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘tosh_acpi_bridge’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:849:2: error: unknown type name ‘acpi_status’
  acpi_status status;
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:853:16: error: ‘AE_OK’ undeclared (first use in this function)
  if (status == AE_OK && (regs->eax & 0xff00) == HCI_SUCCESS)
                ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: At top level:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:1061:33: error: unknown type name ‘acpi_handle’
 static void toshiba_acpi_notify(acpi_handle handle, u32 event, void *context)
                                 ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘toshiba_acpi_setup_keyboard’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:1093:2: error: unknown type name ‘acpi_status’
  acpi_status status;
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:1117:2: error: implicit declaration of function ‘acpi_install_notify_handler’ [-Werror=implicit-function-declaration]
  status = acpi_install_notify_handler(toshiba_acpi.handle,
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:1118:5: error: ‘ACPI_DEVICE_NOTIFY’ undeclared (first use in this function)
     ACPI_DEVICE_NOTIFY, toshiba_acpi_notify, NULL);
     ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:1118:25: error: ‘toshiba_acpi_notify’ undeclared (first use in this function)
     ACPI_DEVICE_NOTIFY, toshiba_acpi_notify, NULL);
                         ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:1141:2: error: implicit declaration of function ‘acpi_remove_notify_handler’ [-Werror=implicit-function-declaration]
  acpi_remove_notify_handler(toshiba_acpi.handle,
  ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘toshiba_acpi_exit’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:1155:5: error: ‘ACPI_DEVICE_NOTIFY’ undeclared (first use in this function)
     ACPI_DEVICE_NOTIFY, toshiba_acpi_notify);
     ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:1155:25: error: ‘toshiba_acpi_notify’ undeclared (first use in this function)
     ACPI_DEVICE_NOTIFY, toshiba_acpi_notify);
                         ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:1171:35: error: ‘acpi_root_dir’ undeclared (first use in this function)
   remove_proc_entry(PROC_TOSHIBA, acpi_root_dir);
                                   ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘toshiba_acpi_init’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:1231:46: error: ‘acpi_root_dir’ undeclared (first use in this function)
  toshiba_proc_dir = proc_mkdir(PROC_TOSHIBA, acpi_root_dir);
                                              ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘version_proc_open’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:828:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/tmp/tmp.85ijquWhNN/toshiba_acpi.c: In function ‘write_acpi_int’:
/tmp/tmp.85ijquWhNN/toshiba_acpi.c:200:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
cc1: some warnings being treated as errors
scripts/Makefile.build:263: recipe for target '/tmp/tmp.85ijquWhNN/toshiba_acpi.o' failed
make[2]: *** [/tmp/tmp.85ijquWhNN/toshiba_acpi.o] Error 1
Makefile:1394: recipe for target '_module_/tmp/tmp.85ijquWhNN' failed
make[1]: *** [_module_/tmp/tmp.85ijquWhNN] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-3.19.0-23-generic'
Makefile:4: recipe for target 'all' failed
make: *** [all] Error 2

Sadly, without toshset I have a 3G modem that's completely unusable. I guess the functionality from this patch never made it into mainline? :\