3 files changed, 23 insertions, 6 deletions

diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index 657964e8ab7e..37fb19047603 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -65,6 +65,7 @@ struct lpss_private_data;
 
 struct lpss_device_desc {
         unsigned int flags;
+        const char *clk_con_id;
         unsigned int prv_offset;
         size_t prv_size_override;
         void (*setup)(struct lpss_private_data *pdata);
@@ -140,6 +141,7 @@ static struct lpss_device_desc lpt_i2c_dev_desc = {
 
 static struct lpss_device_desc lpt_uart_dev_desc = {
         .flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_LTR,
+        .clk_con_id = "baudclk",
         .prv_offset = 0x800,
         .setup = lpss_uart_setup,
 };
@@ -156,6 +158,7 @@ static struct lpss_device_desc byt_pwm_dev_desc = {
 
 static struct lpss_device_desc byt_uart_dev_desc = {
         .flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_SAVE_CTX,
+        .clk_con_id = "baudclk",
         .prv_offset = 0x800,
         .setup = lpss_uart_setup,
 };
@@ -313,7 +316,7 @@ out:
                 return PTR_ERR(clk);
 
         pdata->clk = clk;
-        clk_register_clkdev(clk, NULL, devname);
+        clk_register_clkdev(clk, dev_desc->clk_con_id, devname);
         return 0;
 }
 
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index c723668e3e27..5589a6e2a023 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -42,8 +42,10 @@ static bool acpi_dev_resource_len_valid(u64 start, u64 end, u64 len, bool io)
          * CHECKME: len might be required to check versus a minimum
          * length as well. 1 for io is fine, but for memory it does
          * not make any sense at all.
+         * Note: some BIOSes report incorrect length for ACPI address space
+         * descriptor, so remove check of 'reslen == len' to avoid regression.
          */
-        if (len && reslen && reslen == len && start <= end)
+        if (len && reslen && start <= end)
                 return true;
 
         pr_debug("ACPI: invalid or unassigned resource %s [%016llx - %016llx] length [%016llx]\n",
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index debd30917010..26eb70c8f518 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -2110,7 +2110,8 @@ static int __init intel_opregion_present(void)
 
 int acpi_video_register(void)
 {
-        int result = 0;
+        int ret;
+
         if (register_count) {
                 /*
                  * if the function of acpi_video_register is already called,
@@ -2122,9 +2123,9 @@ int acpi_video_register(void)
         mutex_init(&video_list_lock);
         INIT_LIST_HEAD(&video_bus_head);
 
-        result = acpi_bus_register_driver(&acpi_video_bus);
-        if (result < 0)
-                return -ENODEV;
+        ret = acpi_bus_register_driver(&acpi_video_bus);
+        if (ret)
+                return ret;
 
         /*
          * When the acpi_video_bus is loaded successfully, increase
@@ -2176,6 +2177,17 @@ EXPORT_SYMBOL(acpi_video_unregister_backlight);
 
 static int __init acpi_video_init(void)
 {
+        /*
+         * Let the module load even if ACPI is disabled (e.g. due to
+         * a broken BIOS) so that i915.ko can still be loaded on such
+         * old systems without an AcpiOpRegion.
+         *
+         * acpi_video_register() will report -ENODEV later as well due
+         * to acpi_disabled when i915.ko tries to register itself afterwards.
+         */
+        if (acpi_disabled)
+                return 0;
+
         dmi_check_system(video_dmi_table);
 
         if (intel_opregion_present())