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Message-ID: <CAErSpo75MV2-XvVQdMrcunFbC+bZvPQXmh5Hzt1ihOOjz2pS0w@mail.gmail.com>
Date: Tue, 27 Mar 2012 14:38:49 -0600
From: Bjorn Helgaas <bhelgaas@...gle.com>
To: Witold Szczeponik <Witold.Szczeponik@....net>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/3] PNP: Allow resources to be set as disabled
On Tue, Mar 20, 2012 at 2:00 PM, Witold Szczeponik
<Witold.Szczeponik@....net> wrote:
> This patch allows to set PNP resources as "disabled". As such, the patch is
> a follow-up to commit 18fd470a48396c8795ba7256c5973e92ffa25cb3 where parsing
> of ACPI PNP resources that can be disabled was enabled.
>
> The patch achieves this by doing two things: (1) it allows the strings
> "disabled" and "<none>" to be used as a valid PNP resource value, and (2) when
> assigning PNP resources, it copies the flags masked by IORESOURCE_BITS from the
> resource's templates.
These look like reasonable things to do, but (2) doesn't seem to
depend on (1), so you might just split them into two patches.
> The latter is necessary because the resource settings
> require proper IORESOURCE_BITS which are not known during the definition of
> these resources using the "/sys/bus/pnp/*/*/resources" interface. (In fact,
> they should not be set by the user as the resource templates define the
> proper settings.)
>
> The patch is required in order to support the setting of "disabled" IRQs like
> described in the commit 29df8d8f8702f0f53c1375015f09f04bc8d023c1, i.e., with
> this patch applied, some vintage IBM ThinkPads like the 600E can allocate the
> resources such that all devices can be used simultaneously.
>
> If the second part of the patch is not applied, the resource flags are not
> initialized properly and obscure messages in the kernel log have be seen
s/be/been/
> ("invalid flags").
>
> The patch is applied against Linux 3.3.x.
>
>
> Signed-off-by: Witold Szczeponik <Witold.Szczeponik@....net>
>
>
> Index: linux/drivers/pnp/interface.c
> ===================================================================
> --- linux.orig/drivers/pnp/interface.c
> +++ linux/drivers/pnp/interface.c
> @@ -311,10 +311,14 @@ static char *pnp_get_resource_value(char
> if (flags)
> *flags = 0;
>
> - /* TBD: allow for disabled resources */
> -
> buf = skip_spaces(buf);
> - if (start) {
> + if (flags && !strnicmp(buf, "disabled", 8)) {
> + buf += 8;
> + *flags |= IORESOURCE_DISABLED;
> + } else if (flags && !strnicmp(buf, "<none>", 6)) {
> + buf += 6;
> + *flags |= IORESOURCE_DISABLED;
What's the value in supporting both "disabled" and "<none>"? Having
both suggests that they do different things, but it looks like they
have the same effect.
> + } else if (start) {
> *start = simple_strtoull(buf, &buf, 0);
> if (end) {
> buf = skip_spaces(buf);
> Index: linux/drivers/pnp/manager.c
> ===================================================================
> --- linux.orig/drivers/pnp/manager.c
> +++ linux/drivers/pnp/manager.c
> @@ -18,11 +18,27 @@
>
> DEFINE_MUTEX(pnp_res_mutex);
>
> +static struct resource *pnp_find_resource(struct pnp_dev *dev,
> + unsigned char rule,
> + unsigned long type,
> + unsigned int bar)
> +{
> + struct resource *res = pnp_get_resource(dev, type, bar);
> +
> + /* when the resource already exists, set its resource bits from rule */
> + if (res) {
> + res->flags &= ~IORESOURCE_BITS;
> + res->flags |= rule & IORESOURCE_BITS;
> + }
> +
> + return res;
> +}
> +
> static int pnp_assign_port(struct pnp_dev *dev, struct pnp_port *rule, int idx)
> {
> struct resource *res, local_res;
>
> - res = pnp_get_resource(dev, IORESOURCE_IO, idx);
> + res = pnp_find_resource(dev, rule->flags, IORESOURCE_IO, idx);
> if (res) {
> pnp_dbg(&dev->dev, " io %d already set to %#llx-%#llx "
> "flags %#lx\n", idx, (unsigned long long) res->start,
> @@ -65,7 +81,7 @@ static int pnp_assign_mem(struct pnp_dev
> {
> struct resource *res, local_res;
>
> - res = pnp_get_resource(dev, IORESOURCE_MEM, idx);
> + res = pnp_find_resource(dev, rule->flags, IORESOURCE_MEM, idx);
> if (res) {
> pnp_dbg(&dev->dev, " mem %d already set to %#llx-%#llx "
> "flags %#lx\n", idx, (unsigned long long) res->start,
> @@ -78,6 +94,7 @@ static int pnp_assign_mem(struct pnp_dev
> res->start = 0;
> res->end = 0;
>
> + /* ??? rule->flags restricted to 8 bits, all tests bogus ??? */
> if (!(rule->flags & IORESOURCE_MEM_WRITEABLE))
> res->flags |= IORESOURCE_READONLY;
> if (rule->flags & IORESOURCE_MEM_CACHEABLE)
> @@ -123,7 +140,7 @@ static int pnp_assign_irq(struct pnp_dev
> 5, 10, 11, 12, 9, 14, 15, 7, 3, 4, 13, 0, 1, 6, 8, 2
> };
>
> - res = pnp_get_resource(dev, IORESOURCE_IRQ, idx);
> + res = pnp_find_resource(dev, rule->flags, IORESOURCE_IRQ, idx);
> if (res) {
> pnp_dbg(&dev->dev, " irq %d already set to %d flags %#lx\n",
> idx, (int) res->start, res->flags);
> @@ -182,7 +199,7 @@ static int pnp_assign_dma(struct pnp_dev
> 1, 3, 5, 6, 7, 0, 2, 4
> };
>
> - res = pnp_get_resource(dev, IORESOURCE_DMA, idx);
> + res = pnp_find_resource(dev, rule->flags, IORESOURCE_DMA, idx);
> if (res) {
> pnp_dbg(&dev->dev, " dma %d already set to %d flags %#lx\n",
> idx, (int) res->start, res->flags);
>
--
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