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authorBob Moore <robert.moore@intel.com>2008-07-03 22:48:43 -0400
committerLen Brown <len.brown@intel.com>2008-10-22 23:14:35 -0400
commite56f561736e340a4e923b0db65f65dabf5d94823 (patch)
treea8677ad9130168fb2cdeadfd5cb4b07398db8815 /drivers/acpi/tables
parent237a927682a63f02adb542dbdaafe8a81566451d (diff)
ACPICA: Allow same ACPI table to be loaded/unloaded more than once
Without this change, a table cannot be loaded again once it has been loaded/unloaded one time. The current mechanism does not unregister a table upon an unload. During a load, if the same table is found, this no longer returns an exception. http://www.acpica.org/bugzilla/show_bug.cgi?id=722 Signed-off-by: Bob Moore <robert.moore@intel.com> Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi/tables')
-rw-r--r--drivers/acpi/tables/tbinstal.c49
1 files changed, 42 insertions, 7 deletions
diff --git a/drivers/acpi/tables/tbinstal.c b/drivers/acpi/tables/tbinstal.c
index b22185f55a16..905dc38ab23b 100644
--- a/drivers/acpi/tables/tbinstal.c
+++ b/drivers/acpi/tables/tbinstal.c
@@ -145,6 +145,8 @@ acpi_tb_add_table(struct acpi_table_desc *table_desc, u32 *table_index)
145 } 145 }
146 } 146 }
147 147
148 /* Check for a table match on the entire table length */
149
148 length = ACPI_MIN(table_desc->length, 150 length = ACPI_MIN(table_desc->length,
149 acpi_gbl_root_table_list.tables[i].length); 151 acpi_gbl_root_table_list.tables[i].length);
150 if (ACPI_MEMCMP(table_desc->pointer, 152 if (ACPI_MEMCMP(table_desc->pointer,
@@ -153,17 +155,49 @@ acpi_tb_add_table(struct acpi_table_desc *table_desc, u32 *table_index)
153 continue; 155 continue;
154 } 156 }
155 157
156 /* Table is already registered */ 158 /*
157 159 * Note: the current mechanism does not unregister a table if it is
160 * dynamically unloaded. The related namespace entries are deleted,
161 * but the table remains in the root table list.
162 *
163 * The assumption here is that the number of different tables that
164 * will be loaded is actually small, and there is minimal overhead
165 * in just keeping the table in case it is needed again.
166 *
167 * If this assumption changes in the future (perhaps on large
168 * machines with many table load/unload operations), tables will
169 * need to be unregistered when they are unloaded, and slots in the
170 * root table list should be reused when empty.
171 */
172
173 /*
174 * Table is already registered.
175 * We can delete the table that was passed as a parameter.
176 */
158 acpi_tb_delete_table(table_desc); 177 acpi_tb_delete_table(table_desc);
159 *table_index = i; 178 *table_index = i;
160 status = AE_ALREADY_EXISTS; 179
161 goto release; 180 if (acpi_gbl_root_table_list.tables[i].
181 flags & ACPI_TABLE_IS_LOADED) {
182
183 /* Table is still loaded, this is an error */
184
185 status = AE_ALREADY_EXISTS;
186 goto release;
187 } else {
188 /* Table was unloaded, allow it to be reloaded */
189
190 table_desc->pointer =
191 acpi_gbl_root_table_list.tables[i].pointer;
192 table_desc->address =
193 acpi_gbl_root_table_list.tables[i].address;
194 status = AE_OK;
195 goto print_header;
196 }
162 } 197 }
163 198
164 /* 199 /* Add the table to the global root table list */
165 * Add the table to the global table list 200
166 */
167 status = acpi_tb_store_table(table_desc->address, table_desc->pointer, 201 status = acpi_tb_store_table(table_desc->address, table_desc->pointer,
168 table_desc->length, table_desc->flags, 202 table_desc->length, table_desc->flags,
169 table_index); 203 table_index);
@@ -171,6 +205,7 @@ acpi_tb_add_table(struct acpi_table_desc *table_desc, u32 *table_index)
171 goto release; 205 goto release;
172 } 206 }
173 207
208 print_header:
174 acpi_tb_print_table_header(table_desc->address, table_desc->pointer); 209 acpi_tb_print_table_header(table_desc->address, table_desc->pointer);
175 210
176 release: 211 release: