From: Christoph Hellwig <hch@infradead.org>
To: Ajay Agarwal <ajayagarwal@google.com>
Cc: "Jingoo Han" <jingoohan1@gmail.com>,
"Gustavo Pimentel" <gustavo.pimentel@synopsys.com>,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Rob Herring" <robh@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Manu Gautam" <manugautam@google.com>,
"Sajid Dalvi" <sdalvi@google.com>,
"William McVicker" <willmcvicker@google.com>,
linux-pci@vger.kernel.org
Subject: Re: [PATCH] PCI: dwc: Set DMA mask to 32 only if ZONE_DMA32 is enabled
Date: Thu, 21 Dec 2023 21:05:49 -0800 [thread overview]
Message-ID: <ZYUZLRczqgzO7Gf4@infradead.org> (raw)
In-Reply-To: <20231221174051.35420-1-ajayagarwal@google.com>
On Thu, Dec 21, 2023 at 11:10:51PM +0530, Ajay Agarwal wrote:
> If CONFIG_ZONE_DMA32 is disabled, then the dmam_alloc_coherent
> will fail to allocate the memory if there are no 32-bit addresses
> available. This will lead to the PCIe RC probe failure.
> Fix this by setting the DMA mask to 32 bits only if the kernel
> configuration enables DMA32 zone. Else, leave the mask as is.
And that's why you never must disable ZONE_DMA32 on devices that
can have more than >32bit memory and don't use an iommu for
everything.
NAK.
prev parent reply other threads:[~2023-12-22 5:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-21 17:40 [PATCH] PCI: dwc: Set DMA mask to 32 only if ZONE_DMA32 is enabled Ajay Agarwal
2023-12-21 18:00 ` Ajay Agarwal
2023-12-21 18:05 ` Ajay Agarwal
2023-12-21 18:06 ` Ajay Agarwal
2023-12-21 18:33 ` Serge Semin
2024-01-08 17:50 ` Robin Murphy
2024-01-09 22:47 ` Serge Semin
2024-01-11 3:58 ` Ajay Agarwal
2023-12-22 5:05 ` Christoph Hellwig [this message]
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