79 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			79 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| Subject: [PATCH] [intel_iommu] Default to igfx_off
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| From: drago01 <drago01@gmail.com>
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| To: fedora-kernel-list <fedora-kernel-list@redhat.com>
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| 
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| This option seems to causes way to many issues, it is
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| being investigated by Intel's chipset team for months now and
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| we still don't have any outcome.
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| 
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| The results so far are "black screen when starting X",
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| "system hangs when using GL", "system does not resume".
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| 
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| The patch adds an intel_iommu=igfx_on option, which makes it opt in,
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| rather than opt out.
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| 
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| Signed-off-by: Adel Gadllah <adel.gadllah@gmail.com>
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| Reviewed-by: Adam Jackson <ajax@redhat.com>
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| ---
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|  Documentation/kernel-parameters.txt |   11 +++++------
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|  drivers/pci/intel-iommu.c           |    9 +++++----
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|  2 files changed, 10 insertions(+), 10 deletions(-)
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| 
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| diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
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| index e7848a0..9914485 100644
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| --- a/Documentation/kernel-parameters.txt
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| +++ b/Documentation/kernel-parameters.txt
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| @@ -992,12 +992,11 @@ and is between 256 and 4096 characters. It is defined in the file
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|  			Enable intel iommu driver.
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|  		off
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|  			Disable intel iommu driver.
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| -		igfx_off [Default Off]
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| -			By default, gfx is mapped as normal device. If a gfx
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| -			device has a dedicated DMAR unit, the DMAR unit is
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| -			bypassed by not enabling DMAR with this option. In
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| -			this case, gfx device will use physical address for
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| -			DMA.
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| +		igfx_on [Default Off]
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| +			By default, the gfx's DMAR unit is bypassed by not enabling
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| +			DMAR with this option. So the gfx device will use physical
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| +			address for DMA. When this option is enabled it the gfx is
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| +			mapped as normal device.
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|  		forcedac [x86_64]
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|  			With this option iommu will not optimize to look
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|  			for io virtual address below 32 bit forcing dual
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| diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
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| index 4173125..8f36786 100644
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| --- a/drivers/pci/intel-iommu.c
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| +++ b/drivers/pci/intel-iommu.c
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| @@ -340,7 +340,8 @@ int dmar_disabled = 0;
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|  int dmar_disabled = 1;
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|  #endif /*CONFIG_DMAR_DEFAULT_ON*/
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| 
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| -static int dmar_map_gfx = 1;
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| +/* disabled by default; causes way too many issues */
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| +static int dmar_map_gfx = 0;
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|  static int dmar_forcedac;
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|  static int intel_iommu_strict;
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| 
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| @@ -361,10 +362,10 @@ static int __init intel_iommu_setup(char *str)
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|  		} else if (!strncmp(str, "off", 3)) {
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|  			dmar_disabled = 1;
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|  			printk(KERN_INFO "Intel-IOMMU: disabled\n");
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| -		} else if (!strncmp(str, "igfx_off", 8)) {
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| -			dmar_map_gfx = 0;
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| +		} else if (!strncmp(str, "igfx_on", 7)) {
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| +			dmar_map_gfx = 1;
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|  			printk(KERN_INFO
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| -				"Intel-IOMMU: disable GFX device mapping\n");
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| +				"Intel-IOMMU: enabled GFX device mapping\n");
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|  		} else if (!strncmp(str, "forcedac", 8)) {
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|  			printk(KERN_INFO
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|  				"Intel-IOMMU: Forcing DAC for PCI devices\n");
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| -- 
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| 1.6.6.1
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| _______________________________________________
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| kernel mailing list
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| kernel@lists.fedoraproject.org
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| https://admin.fedoraproject.org/mailman/listinfo/kernel
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| 
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