Re: [PATCH] drm: Fix EDID firmware load on resume

From: Jani Nikula
Date: Thu Oct 06 2022 - 18:23:45 EST

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On Mon, 12 Sep 2022, Matthieu CHARETTE <matthieu.charette@xxxxxxxxx> wrote:
> Hi,
>
> Sorry for late reply.
>
> How do you propose to go then?
> Can we still use a persistent platform device to load the firmware and
> cache it? But, in this case the system will still crash in case the
> user change drm.edid_firmware then, without replugging the device, he
> suspends and resumes the machine.
> Or you may have a better idea?

Maybe. Please try [1]. Could it be as simple as that?

BR,
Jani.

[1] https://patchwork.freedesktop.org/patch/msgid/20221006222146.2375217-1-jani.nikula@xxxxxxxxx

>
> Thanks,
> Matthieu
>
> On Mon, Aug 8 2022 at 08:19:01 PM +0300, Jani Nikula
> <jani.nikula@xxxxxxxxxxxxxxx> wrote:
>> On Mon, 08 Aug 2022, Matthieu CHARETTE <matthieu.charette@xxxxxxxxx>
>> wrote:
>>> Sorry, What do you mean?
>>
>> You cache with one name at connector init time, but the name specified
>> using drm.edid_firmware may be changed whenever, to cause the next
>> EDID
>> read to use a different EDID firmware.
>>
>> BR,
>> Jani.
>>
>>
>>>
>>> Matthieu
>>>
>>> On Tue, Aug 2 2022 at 05:29:12 PM +0300, Jani Nikula
>>> <jani.nikula@xxxxxxxxxxxxxxx> wrote:
>>>> On Wed, 27 Jul 2022, Matthieu CHARETTE <matthieu.charette@xxxxxxxxx
>>>> <mailto:matthieu.charette@xxxxxxxxx>> wrote:
>>>>> Loading an EDID using drm.edid_firmware parameter makes resume to
>>>>> fail
>>>>> after firmware cache is being cleaned. This is because
>>>>> edid_load()
>>>>> use a
>>>>> temporary device to request the firmware. This cause the EDID
>>>>> firmware
>>>>> not to be cached from suspend. And, requesting the EDID firmware
>>>>> return
>>>>> an error during resume.
>>>>> So the request_firmware() call should use a permanent device for
>>>>> each
>>>>> connector. Also, we should cache the EDID even if no monitor is
>>>>> connected, in case it's plugged while suspended.
>>>>
>>>> AFAICT this breaks changing drm.edid_firmware runtime.
>>>>
>>>> BR,
>>>> Jani.
>>>>
>>>>>
>>>>> Link: <https://gitlab.freedesktop.org/drm/amd/-/issues/2061>
>>>>> Signed-off-by: Matthieu CHARETTE <matthieu.charette@xxxxxxxxx
>>>>> <mailto:matthieu.charette@xxxxxxxxx>>
>>>>> ---
>>>>> drivers/gpu/drm/drm_connector.c | 9 ++++
>>>>> drivers/gpu/drm/drm_edid_load.c | 81
>>>>> ++++++++++++++++++++++++++++-----
>>>>> include/drm/drm_connector.h | 12 +++++
>>>>> include/drm/drm_edid.h | 3 ++
>>>>> 4 files changed, 94 insertions(+), 11 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/drm_connector.c
>>>>> b/drivers/gpu/drm/drm_connector.c
>>>>> index 1c48d162c77e..e8819ebf1c4b 100644
>>>>> --- a/drivers/gpu/drm/drm_connector.c
>>>>> +++ b/drivers/gpu/drm/drm_connector.c
>>>>> @@ -31,6 +31,7 @@
>>>>> #include <drm/drm_privacy_screen_consumer.h>
>>>>> #include <drm/drm_sysfs.h>
>>>>>
>>>>> +#include <linux/platform_device.h>
>>>>> #include <linux/uaccess.h>
>>>>>
>>>>> #include "drm_crtc_internal.h"
>>>>> @@ -289,6 +290,9 @@ int drm_connector_init(struct drm_device
>>>>> *dev,
>>>>>
>>>>> drm_connector_get_cmdline_mode(connector);
>>>>>
>>>>> + connector->edid_load_pdev = NULL;
>>>>> + drm_cache_edid_firmware(connector);
>>>>> +
>>>>> /* We should add connectors at the end to avoid upsetting the
>>>>> connector
>>>>> * index too much.
>>>>> */
>>>>> @@ -473,6 +477,11 @@ void drm_connector_cleanup(struct
>>>>> drm_connector *connector)
>>>>> connector->tile_group = NULL;
>>>>> }
>>>>>
>>>>> + if (connector->edid_load_pdev) {
>>>>> + platform_device_unregister(connector->edid_load_pdev);
>>>>> + connector->edid_load_pdev = NULL;
>>>>> + }
>>>>> +
>>>>> list_for_each_entry_safe(mode, t, &connector->probed_modes,
>>>>> head)
>>>>> drm_mode_remove(connector, mode);
>>>>>
>>>>> diff --git a/drivers/gpu/drm/drm_edid_load.c
>>>>> b/drivers/gpu/drm/drm_edid_load.c
>>>>> index 37d8ba3ddb46..5a82be9917ec 100644
>>>>> --- a/drivers/gpu/drm/drm_edid_load.c
>>>>> +++ b/drivers/gpu/drm/drm_edid_load.c
>>>>> @@ -167,6 +167,19 @@ static int edid_size(const u8 *edid, int
>>>>> data_size)
>>>>> return (edid[0x7e] + 1) * EDID_LENGTH;
>>>>> }
>>>>>
>>>>> +static struct platform_device *edid_pdev(const char
>>>>> *connector_name)
>>>>> +{
>>>>> + struct platform_device *pdev =
>>>>> platform_device_register_simple(connector_name, -1, NULL, 0);
>>>>> +
>>>>> + if (IS_ERR(pdev)) {
>>>>> + DRM_ERROR("Failed to register EDID firmware platform device "
>>>>> + "for connector \"%s\"\n", connector_name);
>>>>> + return ERR_CAST(pdev);
>>>>> + }
>>>>> +
>>>>> + return pdev;
>>>>> +}
>>>>> +
>>>>> static void *edid_load(struct drm_connector *connector, const
>>>>> char
>>>>> *name,
>>>>> const char *connector_name)
>>>>> {
>>>>> @@ -182,18 +195,17 @@ static void *edid_load(struct drm_connector
>>>>> *connector, const char *name,
>>>>> fwdata = generic_edid[builtin];
>>>>> fwsize = sizeof(generic_edid[builtin]);
>>>>> } else {
>>>>> - struct platform_device *pdev;
>>>>> + struct platform_device *pdev = connector->edid_load_pdev;
>>>>> int err;
>>>>>
>>>>> - pdev = platform_device_register_simple(connector_name, -1,
>>>>> NULL,
>>>>> 0);
>>>>> - if (IS_ERR(pdev)) {
>>>>> - DRM_ERROR("Failed to register EDID firmware platform device "
>>>>> - "for connector \"%s\"\n", connector_name);
>>>>> - return ERR_CAST(pdev);
>>>>> + if (WARN_ON(!pdev)) {
>>>>> + pdev = edid_pdev(connector_name);
>>>>> + if (IS_ERR(pdev))
>>>>> + return ERR_CAST(pdev);
>>>>> + connector->edid_load_pdev = pdev;
>>>>> }
>>>>>
>>>>> err = request_firmware(&fw, name, &pdev->dev);
>>>>> - platform_device_unregister(pdev);
>>>>> if (err) {
>>>>> DRM_ERROR("Requesting EDID firmware \"%s\" failed
>>>>> (err=%d)\n",
>>>>> name, err);
>>>>> @@ -263,11 +275,9 @@ static void *edid_load(struct drm_connector
>>>>> *connector, const char *name,
>>>>> return edid;
>>>>> }
>>>>>
>>>>> -struct edid *drm_load_edid_firmware(struct drm_connector
>>>>> *connector)
>>>>> +static char *edid_name(const char *connector_name)
>>>>> {
>>>>> - const char *connector_name = connector->name;
>>>>> char *edidname, *last, *colon, *fwstr, *edidstr, *fallback =
>>>>> NULL;
>>>>> - struct edid *edid;
>>>>>
>>>>> if (edid_firmware[0] == '\0')
>>>>> return ERR_PTR(-ENOENT);
>>>>> @@ -310,8 +320,57 @@ struct edid *drm_load_edid_firmware(struct
>>>>> drm_connector *connector)
>>>>> if (*last == '\n')
>>>>> *last = '\0';
>>>>>
>>>>> - edid = edid_load(connector, edidname, connector_name);
>>>>> + edidname = kstrdup(edidname, GFP_KERNEL);
>>>>> + if (!edidname) {
>>>>> + kfree(fwstr);
>>>>> + return ERR_PTR(-ENOMEM);
>>>>> + }
>>>>> +
>>>>> kfree(fwstr);
>>>>> + return edidname;
>>>>> +}
>>>>> +
>>>>> +void drm_cache_edid_firmware(struct drm_connector *connector)
>>>>> +{
>>>>> + const char *connector_name = connector->name;
>>>>> + const char *edidname = edid_name(connector_name);
>>>>> + struct platform_device *pdev;
>>>>> + int err;
>>>>> +
>>>>> + if (IS_ERR(edidname))
>>>>> + return;
>>>>> +
>>>>> + if (match_string(generic_edid_name, GENERIC_EDIDS, edidname) >=
>>>>> 0) {
>>>>> + kfree(edidname);
>>>>> + return;
>>>>> + }
>>>>> +
>>>>> + pdev = edid_pdev(connector_name);
>>>>> + if (IS_ERR(pdev)) {
>>>>> + kfree(edidname);
>>>>> + return;
>>>>> + }
>>>>> + connector->edid_load_pdev = pdev;
>>>>> +
>>>>> + err = firmware_request_cache(&pdev->dev, edidname);
>>>>> + if (err)
>>>>> + DRM_ERROR("Requesting EDID firmware cache \"%s\" failed
>>>>> (err=%d)\n",
>>>>> + edidname, err);
>>>>> +
>>>>> + kfree(edidname);
>>>>> +}
>>>>> +
>>>>> +struct edid *drm_load_edid_firmware(struct drm_connector
>>>>> *connector)
>>>>> +{
>>>>> + const char *connector_name = connector->name;
>>>>> + const char *edidname = edid_name(connector_name);
>>>>> + struct edid *edid;
>>>>> +
>>>>> + if (IS_ERR(edidname))
>>>>> + return ERR_CAST(edidname);
>>>>> +
>>>>> + edid = edid_load(connector, edidname, connector_name);
>>>>> + kfree(edidname);
>>>>>
>>>>> return edid;
>>>>> }
>>>>> diff --git a/include/drm/drm_connector.h
>>>>> b/include/drm/drm_connector.h
>>>>> index 3ac4bf87f257..47c84741517e 100644
>>>>> --- a/include/drm/drm_connector.h
>>>>> +++ b/include/drm/drm_connector.h
>>>>> @@ -1573,6 +1573,18 @@ struct drm_connector {
>>>>> */
>>>>> struct i2c_adapter *ddc;
>>>>>
>>>>> + /**
>>>>> + * @edid_load_pdev: Platform device for loading EDID via
>>>>> firmware.
>>>>> + *
>>>>> + * The platform device is registered in drm_connector_init() in
>>>>> case a
>>>>> + * custom EDID firmware is used with `edid_firmware` parameter.
>>>>> Otherwise,
>>>>> + * it is set to NULL.
>>>>> + *
>>>>> + * Platform device is unregistered in drm_connector_cleanup()
>>>>> if
>>>>> it
>>>>> + * is not NULL.
>>>>> + */
>>>>> + struct platform_device *edid_load_pdev;
>>>>> +
>>>>> /**
>>>>> * @null_edid_counter: track sinks that give us all zeros for
>>>>> the
>>>>> EDID.
>>>>> * Needed to workaround some HW bugs where we get all 0s
>>>>> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
>>>>> index b2756753370b..e907c928a35d 100644
>>>>> --- a/include/drm/drm_edid.h
>>>>> +++ b/include/drm/drm_edid.h
>>>>> @@ -378,10 +378,13 @@ int drm_av_sync_delay(struct drm_connector
>>>>> *connector,
>>>>> const struct drm_display_mode *mode);
>>>>>
>>>>> #ifdef CONFIG_DRM_LOAD_EDID_FIRMWARE
>>>>> +void drm_cache_edid_firmware(struct drm_connector *connector);
>>>>> struct edid *drm_load_edid_firmware(struct drm_connector
>>>>> *connector);
>>>>> int __drm_set_edid_firmware_path(const char *path);
>>>>> int __drm_get_edid_firmware_path(char *buf, size_t bufsize);
>>>>> #else
>>>>> +inline void
>>>>> +drm_cache_edid_firmware(struct drm_connector *connector);
>>>>> static inline struct edid *
>>>>> drm_load_edid_firmware(struct drm_connector *connector)
>>>>> {
>>>>
>>>> --
>>>> Jani Nikula, Intel Open Source Graphics Center
>>>
>>
>> --
>> Jani Nikula, Intel Open Source Graphics Center
>
>

--
Jani Nikula, Intel Open Source Graphics Center

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