[PATCH] drm/tegra: add MODULE_DEVICE_TABLEs

[Thierry Reding]

On Wed, Jun 18, 2014 at 04:21:18PM -0600, Stephen Warren wrote:
> On 06/18/2014 03:51 PM, Thierry Reding wrote:
> > On Wed, Jun 18, 2014 at 03:19:15PM -0600, Stephen Warren wrote:
> >> From: Stephen Warren 
> >>
> >> When tegra-drm.ko is built as a module, these MODULE_DEVICE_TABLEs allow
> >> the module to be auto-loaded since the module will match the devices
> >> instantiated from device tree.
> > 
> > I vaguely remember doing something like this a while back and getting a
> > bunch of link-time errors. But I assume that you've tested this, so I
> > must be remembering wrongly.
> 
> Were the problems due to:
> 
> a) Simply building the tegradrm driver as modules.
> 
> I vaguely recall some runtime issues with tegradrm as a module, but I'm
> not sure about build issues. I don't think this patch could make this
> any worse.
> 
> b) Building as modules works, but adding MODULE_DEVICE_TABLE broke that.

I think it was this variant. Although adding MODULE_DEVICE_TABLE also
broke building the driver as builtin module. I think the issue was that
the linker was complaining about some symbol being defined multiple
times. But admittedly this was a long time ago, so I'm not sure that my
memory is entirely accurate.

> This seems unlikely since *many* module in the kernel have a
> MODULE_DEVICE_TABLE...
> 
> Certainly, with this patch applied, building tegradrm as a module in
> next-20140611 works out just fine, and the code runs fine too. Building
> tegra_defconfig (which has tegradrm builtin) on Linus' master with this
> patch applied also works out fine.

Okay, sounds good then. I'll do some build testing to see if I can
reproduce the errors, otherwise this looks good to me.

Thierry
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[PATCH] drm/tegra: add MODULE_DEVICE_TABLEs

[Thierry Reding]

On Wed, Jun 18, 2014 at 03:19:15PM -0600, Stephen Warren wrote:
> From: Stephen Warren 
> 
> When tegra-drm.ko is built as a module, these MODULE_DEVICE_TABLEs allow
> the module to be auto-loaded since the module will match the devices
> instantiated from device tree.

I vaguely remember doing something like this a while back and getting a
bunch of link-time errors. But I assume that you've tested this, so I
must be remembering wrongly.

One comment below:

> diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
> index 3396f9f6a9f7..a1f9b06a75d5 100644
> --- a/drivers/gpu/drm/tegra/drm.c
> +++ b/drivers/gpu/drm/tegra/drm.c
> @@ -694,6 +694,7 @@ static const struct of_device_id host1x_drm_subdevs[] = {
>   { .compatible = "nvidia,tegra124-hdmi", },
>   { /* sentinel */ }
>  };
> +MODULE_DEVICE_TABLE(of, host1x_drm_subdevs);

I don't think this one is really required. It's a union of all other
compatible values and only used to delay the DRM subsystem driver
registration until all needed subdevices have been probed.

Thierry
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[PATCH] drm/tegra: add MODULE_DEVICE_TABLEs

[Stephen Warren]

On 06/18/2014 03:51 PM, Thierry Reding wrote:
> On Wed, Jun 18, 2014 at 03:19:15PM -0600, Stephen Warren wrote:
>> From: Stephen Warren 
>>
>> When tegra-drm.ko is built as a module, these MODULE_DEVICE_TABLEs allow
>> the module to be auto-loaded since the module will match the devices
>> instantiated from device tree.
> 
> I vaguely remember doing something like this a while back and getting a
> bunch of link-time errors. But I assume that you've tested this, so I
> must be remembering wrongly.

Were the problems due to:

a) Simply building the tegradrm driver as modules.

I vaguely recall some runtime issues with tegradrm as a module, but I'm
not sure about build issues. I don't think this patch could make this
any worse.

b) Building as modules works, but adding MODULE_DEVICE_TABLE broke that.

This seems unlikely since *many* module in the kernel have a
MODULE_DEVICE_TABLE...

Certainly, with this patch applied, building tegradrm as a module in
next-20140611 works out just fine, and the code runs fine too. Building
tegra_defconfig (which has tegradrm builtin) on Linus' master with this
patch applied also works out fine.

I'll post v2 with the issue you mentioned addressed.

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[PATCH] drm/tegra: add MODULE_DEVICE_TABLEs

[Stephen Warren]

From: Stephen Warren 

When tegra-drm.ko is built as a module, these MODULE_DEVICE_TABLEs allow
the module to be auto-loaded since the module will match the devices
instantiated from device tree.

(Notes for stable: in 3.14+, just git rm any conflicting file, since they
are added in later kernels. For 3.13 and below, manual merging will be
needed)

Cc: 
Signed-off-by: Stephen Warren 
---
 drivers/gpu/drm/tegra/dc.c| 1 +
 drivers/gpu/drm/tegra/dpaux.c | 1 +
 drivers/gpu/drm/tegra/drm.c   | 1 +
 drivers/gpu/drm/tegra/dsi.c   | 1 +
 drivers/gpu/drm/tegra/gr2d.c  | 1 +
 drivers/gpu/drm/tegra/gr3d.c  | 1 +
 drivers/gpu/drm/tegra/hdmi.c  | 1 +
 drivers/gpu/drm/tegra/sor.c   | 1 +
 8 files changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index ef40381f3909..48c3bc460eef 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -1303,6 +1303,7 @@ static const struct of_device_id tegra_dc_of_match[] = {
/* sentinel */
}
 };
+MODULE_DEVICE_TABLE(of, tegra_dc_of_match);

 static int tegra_dc_parse_dt(struct tegra_dc *dc)
 {
diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
index 3f132e356e9c..708f783ead47 100644
--- a/drivers/gpu/drm/tegra/dpaux.c
+++ b/drivers/gpu/drm/tegra/dpaux.c
@@ -382,6 +382,7 @@ static const struct of_device_id tegra_dpaux_of_match[] = {
{ .compatible = "nvidia,tegra124-dpaux", },
{ },
 };
+MODULE_DEVICE_TABLE(of, tegra_dpaux_of_match);

 struct platform_driver tegra_dpaux_driver = {
.driver = {
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index 3396f9f6a9f7..a1f9b06a75d5 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -694,6 +694,7 @@ static const struct of_device_id host1x_drm_subdevs[] = {
{ .compatible = "nvidia,tegra124-hdmi", },
{ /* sentinel */ }
 };
+MODULE_DEVICE_TABLE(of, host1x_drm_subdevs);

 static struct host1x_driver host1x_drm_driver = {
.name = "drm",
diff --git a/drivers/gpu/drm/tegra/dsi.c b/drivers/gpu/drm/tegra/dsi.c
index bd56f2affa78..97c409f10456 100644
--- a/drivers/gpu/drm/tegra/dsi.c
+++ b/drivers/gpu/drm/tegra/dsi.c
@@ -982,6 +982,7 @@ static const struct of_device_id tegra_dsi_of_match[] = {
{ .compatible = "nvidia,tegra114-dsi", },
{ },
 };
+MODULE_DEVICE_TABLE(of, tegra_dsi_of_match);

 struct platform_driver tegra_dsi_driver = {
.driver = {
diff --git a/drivers/gpu/drm/tegra/gr2d.c b/drivers/gpu/drm/tegra/gr2d.c
index 7c53941f2a9e..02cd3e37a6ec 100644
--- a/drivers/gpu/drm/tegra/gr2d.c
+++ b/drivers/gpu/drm/tegra/gr2d.c
@@ -121,6 +121,7 @@ static const struct of_device_id gr2d_match[] = {
{ .compatible = "nvidia,tegra20-gr2d" },
{ },
 };
+MODULE_DEVICE_TABLE(of, gr2d_match);

 static const u32 gr2d_addr_regs[] = {
GR2D_UA_BASE_ADDR,
diff --git a/drivers/gpu/drm/tegra/gr3d.c b/drivers/gpu/drm/tegra/gr3d.c
index 30f5ba9bd6d0..2bea2b2d204e 100644
--- a/drivers/gpu/drm/tegra/gr3d.c
+++ b/drivers/gpu/drm/tegra/gr3d.c
@@ -130,6 +130,7 @@ static const struct of_device_id tegra_gr3d_match[] = {
{ .compatible = "nvidia,tegra20-gr3d" },
{ }
 };
+MODULE_DEVICE_TABLE(of, tegra_gr3d_match);

 static const u32 gr3d_addr_regs[] = {
GR3D_IDX_ATTRIBUTE( 0),
diff --git a/drivers/gpu/drm/tegra/hdmi.c b/drivers/gpu/drm/tegra/hdmi.c
index ba067bb767e3..ffe26547328d 100644
--- a/drivers/gpu/drm/tegra/hdmi.c
+++ b/drivers/gpu/drm/tegra/hdmi.c
@@ -1450,6 +1450,7 @@ static const struct of_device_id tegra_hdmi_of_match[] = {
{ .compatible = "nvidia,tegra20-hdmi", .data = _hdmi_config },
{ },
 };
+MODULE_DEVICE_TABLE(of, tegra_hdmi_of_match);

 static int tegra_hdmi_probe(struct platform_device *pdev)
 {
diff --git a/drivers/gpu/drm/tegra/sor.c b/drivers/gpu/drm/tegra/sor.c
index 27c979b50111..061a5c501124 100644
--- a/drivers/gpu/drm/tegra/sor.c
+++ b/drivers/gpu/drm/tegra/sor.c
@@ -1455,6 +1455,7 @@ static const struct of_device_id tegra_sor_of_match[] = {
{ .compatible = "nvidia,tegra124-sor", },
{ },
 };
+MODULE_DEVICE_TABLE(of, tegra_sor_of_match);

 struct platform_driver tegra_sor_driver = {
.driver = {
-- 
1.8.1.5