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From: Adrian Hunter <adrian.hunter@intel.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
	Chris Ball <chris@printf.net>,
	linux-mmc <linux-mmc@vger.kernel.org>
Subject: Re: [PATCH 00/15] mmc: sdhci: Add 64-bit ADMA support
Date: Thu, 30 Oct 2014 14:55:44 +0200	[thread overview]
Message-ID: <54523550.5010002@intel.com> (raw)
In-Reply-To: <2048776.ZjHxKvTX0Z@wuerfel>

On 30/10/14 14:15, Arnd Bergmann wrote:
> On Thursday 30 October 2014 12:50:59 Adrian Hunter wrote:
>> On 30/10/14 12:00, Arnd Bergmann wrote:
>>>
>>> You also said that the flag is defined to mean that 64-bit DMA
>>> is working and that you want to show the warning when the hardware
>>> and the firmware disagree about this.  If you have an (at least)
>>> 50% chance that the hardware is lying, you really shouldn't believe
>>> it.
>>
>> Just because there are two options does not mean they are each equally
>> likely.
>>
> 
> Yes, that's why I said "at least". Presumably when the hardware and
> firmware disagree about something, it's because the firmware developer
> found a problem with the hardware and wants to work around that.

No, the capability bit could be set by firmware and the DMA restriction
could be broken software, which would make the situation quite different.

sdhci.c will also accept the capabilities bits coming from another source.

Nevertheless, the programming is for non-broken hardware and the
SDHCI_QUIRK2_BROKEN_64_BIT_DMA will suffice otherwise.


  reply	other threads:[~2014-10-30 12:57 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-21  9:26 [PATCH 00/15] mmc: sdhci: Add 64-bit ADMA support Adrian Hunter
2014-10-21  9:26 ` [PATCH 01/15] mmc: sdhci: Fix incorrect ADMA2 descriptor table size Adrian Hunter
2014-10-21  9:26 ` [PATCH 02/15] mmc: sdhci: Fix ADMA page boundary warnings Adrian Hunter
2014-10-21  9:26 ` [PATCH 03/15] mmc: sdhci: Fix ADMA table size warning Adrian Hunter
2014-10-21  9:26 ` [PATCH 04/15] mmc: sdhci: Rename two ADMA-related functions for consistency Adrian Hunter
2014-10-21  9:26 ` [PATCH 05/15] mmc: sdhci: Rename adma_desc to adma_table Adrian Hunter
2014-10-21  9:26 ` [PATCH 06/15] mmc: sdhci: Add sdhci_adma_mark_end() Adrian Hunter
2014-10-21  9:26 ` [PATCH 07/15] mmc: sdhci: Use 'void *' for not 'u8 *' for ADMA data Adrian Hunter
2014-10-21  9:26 ` [PATCH 08/15] mmc: sdhci: Parameterize ADMA sizes and alignment Adrian Hunter
2014-10-21  9:26 ` [PATCH 09/15] mmc: sdhci: Define maximum segments Adrian Hunter
2014-10-21  9:26 ` [PATCH 10/15] mmc: sdhci: Define ADMA constants Adrian Hunter
2014-10-21  9:26 ` [PATCH 11/15] mmc: sdhci: Define ADMA descriptor structure Adrian Hunter
2014-10-21  9:26 ` [PATCH 12/15] mmc: sdhci: Add 64-bit ADMA support Adrian Hunter
2014-10-21  9:26 ` [PATCH 13/15] mmc: sdhci-acpi: Add 64-bit DMA support Adrian Hunter
2014-10-21  9:33   ` Arnd Bergmann
2014-10-21 10:45     ` Adrian Hunter
2014-10-21 11:05       ` Arnd Bergmann
2014-10-28  8:37         ` [PATCH V2] " Adrian Hunter
2014-10-28  9:43           ` Arnd Bergmann
2014-10-28 10:05             ` Adrian Hunter
2014-10-28 10:18               ` Arnd Bergmann
2014-10-28 11:41                 ` Adrian Hunter
2014-10-28 13:54                   ` Arnd Bergmann
2014-10-28 14:14                     ` Adrian Hunter
2014-10-28 15:08                       ` Arnd Bergmann
2014-10-28 15:14                         ` Adrian Hunter
2014-10-28 15:38                           ` Arnd Bergmann
2014-10-29  8:53                             ` Adrian Hunter
2014-10-21  9:26 ` [PATCH 14/15] mmc: sdhci-pci: " Adrian Hunter
2014-10-21  9:26 ` [PATCH 15/15] mmc: mmc_test: Extend "Badly aligned" tests for 8-byte alignment Adrian Hunter
2014-10-30  7:25 ` [PATCH 00/15] mmc: sdhci: Add 64-bit ADMA support Adrian Hunter
2014-10-30  8:05   ` Arnd Bergmann
2014-10-30  8:40     ` Adrian Hunter
2014-10-30 10:00       ` Arnd Bergmann
2014-10-30 10:50         ` Adrian Hunter
2014-10-30 12:15           ` Arnd Bergmann
2014-10-30 12:55             ` Adrian Hunter [this message]
2014-11-03  8:28   ` Adrian Hunter
2014-11-03 14:40     ` Ulf Hansson

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