mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Unai Uribarri <unai.uribarri@optenet.com>
To: linux-kernel@vger.kernel.org
Subject: Workaround hardware bug addressing physical address
Date: Wed, 14 Jul 2010 12:50:18 +0200 (CEST)	[thread overview]
Message-ID: <7112439.65171279104617973.JavaMail.root@mail1-md.optenet.com> (raw)
In-Reply-To: <3152203.65151279104029659.JavaMail.root@mail1-md.optenet.com>

Hello, 

I'm writing a device driver for a Cavium Octeon 56xx network adapter, which has a silicon bug: it sends invalid PCI Express TLP headers when writing to physical addresses between 2GB and 4GB. It sends a 64 bit memory write when the PCI specs mandates a 32 bit memory write, and some PCIe bridges refuses such transactions (at least Intel 5520/X58 refuses them). 

Now, when allocating memory using alloc_page, I check the allocated memory and leak the unusable pages. This "solution" works but I'm leaking huge amounts of memory, so I'm planning to adopt a more elegant solution. I'm going to link together all the unusable pages and, after all the memory is allocated, free the unusable pages.

Do someone knows if more hardware shares this bug? Will a generic solution be useful for other hardware that doesn't accept certain zones of memory? Has anyone already developed such solution?

Thanks.

       reply	other threads:[~2010-07-14 11:21 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <3152203.65151279104029659.JavaMail.root@mail1-md.optenet.com>
2010-07-14 10:50 ` Unai Uribarri [this message]
     [not found] <28112199.68371279127209288.JavaMail.root@mail1-md.optenet.com>
2010-07-14 17:07 ` Unai Uribarri
2010-07-14 18:18 ` Marin Mitov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=7112439.65171279104617973.JavaMail.root@mail1-md.optenet.com \
    --to=unai.uribarri@optenet.com \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome