linux-kernel - Radeon kernel-modesetting on Alpha. Problem reading PCI ROM

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Date:	Tue, 14 Apr 2009 16:15:57 -0400
From:	Matt Turner <mattst88@...il.com>
To:	linux-kernel@...r.kernel.org, linux-alpha@...r.kernel.org,
	dri-devel@...ts.sourceforge.net
Cc:	Richard Henderson <rth@...ddle.net>,
	Ivan Kokshaysky <ink@...assic.park.msu.ru>,
	Jay Estabrook <jay.estabrook@...com>,
	Oliver Falk <oliver@...ux-kernel.at>, glisse@...edesktop.org
Subject: Radeon kernel-modesetting on Alpha. Problem reading PCI ROM

Hi,

I'm testing Jerome Glisse's drm-next-radeon branch which provides
Radeon Kernel-modesetting support on a Samsung UP1500 with a PCI
Radeon X1550.

See http://cgit.freedesktop.org/~glisse/drm-next/log/?h=drm-next-radeon

While doing so, I've hit a few snags, and placed DRM_INFOs and printks
throughout code in question. On Alpha, it hangs after calling
fb_notifier_call_chain in register_framebuffer.

Jerome and I think that the hang may be caused by being unable to read
the PCI ROM.

The radeon_read_bios function makes use of pci_map_rom, which calls
pci_get_rom_size. In pci_get_rom_size, readb(image) doesn't return
0x55. It falls back to read_disabled functions which appear to
succeed.

Why would the ROM not be able to be read by readb? Is this a general
problem, or Alpha-specific?

Attached are relevant dmesg logs and printk patches (against commit
7582b4332602dcf03bb0c79f17e0cf89eeec6623) to give context.

Thanks,

Matt Turner

Download attachment "radeon-kms.log" of type "application/octet-stream" (2574 bytes)

Download attachment "radeon-kms-debugging.patch" of type "application/octet-stream" (2618 bytes)