40 lines
		
	
	
		
			1.4 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			40 lines
		
	
	
		
			1.4 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| From 1e494dc5f3140005ff1f17bc06c0c16d6d50d580 Mon Sep 17 00:00:00 2001
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| From: Mark Salter <msalter@redhat.com>
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| Date: Thu, 19 Apr 2018 23:29:47 -0400
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| Subject: [PATCH] ACPI / scan: Fix regression related to X-Gene UARTs
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| 
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| Commit e361d1f85855 ("ACPI / scan: Fix enumeration for special UART
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| devices") caused a regression with some X-Gene based platforms (Mustang
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| and M400) with invalid DSDT. The DSDT makes it appear that the UART
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| device is also a slave device attached to itself. With the above commit
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| the UART won't be enumerated by ACPI scan (slave serial devices shouldn't
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| be). So check for X-Gene UART device and skip slace device check on it.
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| 
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| Signed-off-by: Mark Salter <msalter@redhat.com>
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| ---
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|  drivers/acpi/scan.c | 8 ++++++++
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|  1 file changed, 8 insertions(+)
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| 
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| diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
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| index e1b6231cfa1c..542dafac4306 100644
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| --- a/drivers/acpi/scan.c
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| +++ b/drivers/acpi/scan.c
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| @@ -1567,6 +1567,14 @@ static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
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|  	if (!acpi_match_device_ids(device, i2c_multi_instantiate_ids))
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|  		return false;
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|  
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| +	/*
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| +	 * Firmware on some arm64 X-Gene platforms will make the UART
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| +	 * device appear as both a UART and a slave of that UART. Just
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| +	 * bail out here for X-Gene UARTs.
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| +	 */
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| +	if (!strcmp(acpi_device_hid(device), "APMC0D08"))
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| +		return false;
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| +
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|  	INIT_LIST_HEAD(&resource_list);
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|  	acpi_dev_get_resources(device, &resource_list,
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|  			       acpi_check_serial_bus_slave,
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| -- 
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| 2.17.1
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| 
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