Andrew Morton wrote:
On Mon, 18 Jan 2010 12:34:13 -0600
Mike Travis <travis@xxxxxxx> wrote:
Update pci_set_vga_state to call arch dependent functions to enable
Legacy VGA I/O transactions to be redirected to correct target.
Changelog doesn't explain the reason for doing this, but it looks like
that becomes clearer in later patches.
You're right, I should have carried more from the intro page into the
actual patch.
+/* Some architectures require additional programming to enable VGA */
+static arch_set_vga_state_t arch_set_vga_state;
+
+void pci_register_set_vga_state(arch_set_vga_state_t func)
+{
+ arch_set_vga_state = func; /* NULL disables */
+}
+
+static int pci_set_vga_state_arch(struct pci_dev *dev, bool decode,
+ unsigned int command_bits, bool change_bridge)
+{
+ if (arch_set_vga_state)
+ return arch_set_vga_state(dev, decode, command_bits,
+ change_bridge);
+ return 0;
+}
hm, that's not terribly elegant. It's racy too, although it seems
unlikely that an arch will call pci_set_vga_state_arch() more than
once.
Yes, it's only set (once) if it is a UV system.
Still, a neater solution might be
int arch_pci_set_vga_state(...) __weak
{
return 0;
}
and then resolve it at linkage time?
Wouldn't the linked in stronger function then need to surround
the UV register updating with "if (uv_system)"?
Thanks for the comments Andrew.
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