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Subject: Re: [PATCH 1/7] cxlflash: Simplify PCI registration
To: linux-scsi@vger.kernel.org,
 James Bottomley <James.Bottomley@HansenPartnership.com>,
 "Martin K. Petersen" <martin.petersen@oracle.com>,
 "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>,
 "Manoj N. Kumar" <manoj@linux.vnet.ibm.com>
References: <1457128424-53017-1-git-send-email-ukrishn@linux.vnet.ibm.com>
 <1457128520-53056-1-git-send-email-ukrishn@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, Brian King <brking@linux.vnet.ibm.com>,
 Ian Munsie <imunsie@au1.ibm.com>,
 Andrew Donnellan <andrew.donnellan@au1.ibm.com>,
 Frederic Barrat <fbarrat@linux.vnet.ibm.com>,
 Christophe Lombard <clombard@linux.vnet.ibm.com>
From: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Message-ID: <56DF11E6.2010907@linux.vnet.ibm.com>
Date: Tue, 8 Mar 2016 11:54:46 -0600
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On 3/4/2016 3:55 PM, Uma Krishnan wrote:
> From: "Manoj N. Kumar" <manoj@linux.vnet.ibm.com>
>
> The calls to pci_request_regions(), pci_resource_start(),
> pci_set_dma_mask(), pci_set_master() and pci_save_state() are all
> unnecessary for the IBM CXL flash adapter since data buffers
> are not required to be mapped to the device's memory.
>
> The use of services such as pci_set_dma_mask() are problematic on
> hypervisor managed systems as the IBM CXL flash adapter is operating
> under a virtual PCI Host Bridge (virtual PHB) which does not support
> these services.
>
> cxlflash 0001:00:00.0: init_pci: Failed to set PCI DMA mask rc=-5
>
> The resolution is to simplify init_pci(), to a point where it does the
> bare minimum (pci_enable_device). Similarly, remove the call the
> pci_release_regions() from cxlflash_remove().
>
> Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>

Reviewed-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>