Re: [igt-dev] [PATCH i-g-t 3/9] lib/igt_pm: D3Cold runtime pm infrastructure

["Gupta, Anshuman" <anshuman.gupta@intel.com>]

> -----Original Message-----
> From: Vivi, Rodrigo <rodrigo.vivi@intel.com>
> Sent: Friday, April 22, 2022 3:47 PM
> To: Gupta, Anshuman <anshuman.gupta@intel.com>
> Cc: igt-dev@lists.freedesktop.org; Nilawar, Badal <badal.nilawar@intel.com>
> Subject: Re: [igt-dev] [PATCH i-g-t 3/9] lib/igt_pm: D3Cold runtime pm
> infrastructure
> 
> On Mon, Apr 18, 2022 at 06:20:42PM +0530, Anshuman Gupta wrote:
> > Enable gfx card pci devices runtime pm for all pci devices and bridge
> > under the topology of Gfx Card root port.
> >
> > Added a library function to get the PCI root port ACPI D state and to
> > print the pci card devices runtime pm status.
> >
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
> > ---
> >  lib/igt_pm.c | 226
> > +++++++++++++++++++++++++++++++++++++++++++++++++++
> >  lib/igt_pm.h |  21 +++++
> >  2 files changed, 247 insertions(+)
> >
> > diff --git a/lib/igt_pm.c b/lib/igt_pm.c index b409ec463..8e8a330f8
> > 100644
> > --- a/lib/igt_pm.c
> > +++ b/lib/igt_pm.c
> > @@ -28,6 +28,7 @@
> >  #include <fcntl.h>
> >  #include <stdio.h>
> >  #include <limits.h>
> > +#include <pciaccess.h>
> >  #include <stdlib.h>
> >  #include <string.h>
> >  #include <unistd.h>
> > @@ -75,6 +76,7 @@ enum {
> >  #define MIN_POWER_STR		"min_power\n"
> >  /* Remember to fix this if adding longer strings */
> >  #define MAX_POLICY_STRLEN	strlen(MAX_PERFORMANCE_STR)
> > +#define MAX_PCI_DEVICES		256
> >  int8_t *__sata_pm_policies;
> >  int __scsi_host_cnt;
> >
> > @@ -856,3 +858,227 @@ bool i915_output_is_lpsp_capable(int drm_fd,
> > igt_output_t *output)
> >
> >  	return strstr(buf, "LPSP: capable");  }
> > +
> > +/**
> > + * igt_pm_acpi_d3cold_suppoarted:
> 
>                               ^ typo
> 
> > + * @pci_dev: root port pci_dev.
> > + * Check ACPI D3Cold support.
> > + *
> > + * Returns:
> > + * True if ACPI D3Cold supported otherwise false.
> > + */
> > +bool igt_pm_acpi_d3cold_supported(struct pci_device *pci_dev) {
> > +	char name[PATH_MAX];
> > +	int dir, fd;
> > +
> > +	snprintf(name, PATH_MAX,
> > +
> "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/firmware_node",
> > +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
> > +
> > +	dir = open(name, O_RDONLY);
> > +	igt_require(dir > 0);
> > +
> > +	/* BIOS need to enable ACPI D3Cold Support.*/
> > +	fd = openat(dir, "real_power_state", O_RDONLY);
> > +	if (fd < 0 && errno == ENOENT)
> > +		return false;
> > +
> > +	igt_require(fd > 0);
> > +
> > +	return true;
> > +}
> > +
> > +/**
> > + * igt_pm_get_acpi_real_d_state:
> > + * @pci_dev: root port pci_dev.
> > + * Get ACPI D state for a given root port.
> > + *
> > + * Returns:
> > + * igt_acpi_d_state state.
> > + */
> > +enum igt_acpi_d_state
> > +igt_pm_get_acpi_real_d_state(struct pci_device *pci_dev) {
> > +	char name[PATH_MAX];
> > +	char acpi_d_state[64];
> > +	int fd, n_read;
> > +
> > +	snprintf(name, PATH_MAX,
> > +
> "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/firmware_node/real_power_stat
> e",
> > +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
> > +
> > +	fd = open(name, O_RDONLY);
> > +	if (fd < 0)
> > +		return IGT_ACPI_UNKNOWN_STATE;
> > +
> > +	n_read = read(fd, acpi_d_state, sizeof(acpi_d_state) - 1);
> > +	igt_assert(n_read >= 0);
> > +	acpi_d_state[n_read] = '\0';
> > +	close(fd);
> > +
> > +	if (strncmp(acpi_d_state, "D0\n", n_read) == 0)
> > +		return IGT_ACPI_D0;
> > +	else if  (strncmp(acpi_d_state, "D1\n", n_read) == 0)
> > +		return IGT_ACPI_D1;
> > +	else if  (strncmp(acpi_d_state, "D2\n", n_read) == 0)
> > +		return IGT_ACPI_D2;
> > +	else if  (strncmp(acpi_d_state, "D3hot\n", n_read) == 0)
> > +		return IGT_ACPI_D3Hot;
> > +	else if  (strncmp(acpi_d_state, "D3cold\n", n_read) == 0)
> > +		return IGT_ACPI_D3Cold;
> > +	else
> > +		return IGT_ACPI_UNKNOWN_STATE;
> > +}
> > +
> > +static struct igt_pm_pci_dev_control
> > +__igt_pm_pci_control[MAX_PCI_DEVICES];
> 
> the only thing that I'm not totally comfortable with this patch is this global struct
> of 256 items in a lib file.
Thanks for comment, sole purpose of this array to restore the states.
Will a dynamic allocated buffer will address your concern ?
Which can be freed-up on restoring the attributes.
Thanks,
Anshuman Gupta.
> 
> Although I liked the use of the exit handler to restore the status...
> 
> > +
> > +static void __igt_pm_pci_card_exit_handler(int sig) {
> > +	igt_pm_restore_pci_card_runtime_pm();
> > +}
> > +
> > +static void
> > +__igt_pm_setup_pci_card_runtime_pm(struct pci_device *pci_dev, int
> > +index) {
> > +	char name[PATH_MAX], buf[6];
> > +	int fd, control_size, size;
> > +	char *control;
> > +
> > +	igt_assert(index <  MAX_PCI_DEVICES);
> > +
> > +	control = __igt_pm_pci_control[index].control;
> > +	control_size =  sizeof(__igt_pm_pci_control[index].control);
> > +	__igt_pm_pci_control[index].pci_dev = pci_dev;
> > +
> > +	snprintf(name, PATH_MAX,
> "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/power/control",
> > +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
> > +
> > +	fd = open(name, O_RDWR);
> > +	igt_assert_f(fd >= 0, "Can't open control\n");
> > +
> > +	igt_assert(read(fd, control, control_size - 1) > 0);
> > +	strchomp(control);
> > +
> > +	igt_debug("Saved runtime power management for PCI
> '%04x:%02x:%02x.%01x' '%s'\n",
> > +		  pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func,
> control);
> > +	igt_install_exit_handler(__igt_pm_pci_card_exit_handler);
> > +
> > +	size = write(fd, "auto\n", 5);
> > +	igt_assert(size == 5);
> > +
> > +	lseek(fd, 0, SEEK_SET);
> > +	size = read(fd, buf, ARRAY_SIZE(buf));
> > +	igt_assert(size == 5);
> > +	igt_assert(strncmp(buf, "auto\n", 5) == 0);
> > +
> > +	close(fd);
> > +}
> > +
> > +/**
> > + * igt_pm_setup_pci_card_runtime_pm:
> > + * @pci_dev: root port pci_dev.
> > + * Setup runtime PM for all PCI endpoints devices for a given
> > + * root port. It also save power control attribute for all PCI
> > +endpoints
> > + * devices for a given root port.
> > + */
> > +void igt_pm_setup_pci_card_runtime_pm(struct pci_device *pci_dev) {
> > +	int primary, secondary, subordinate, ret;
> > +	struct pci_device_iterator *iter;
> > +	struct pci_device *dev;
> > +	int i = 0;
> > +
> > +	memset(__igt_pm_pci_control, 0, sizeof(__igt_pm_pci_control));
> > +	ret = pci_device_get_bridge_buses(pci_dev, &primary, &secondary,
> &subordinate);
> > +	igt_assert(!ret);
> > +
> > +	ret = pci_system_init();
> > +	igt_assert(!ret);
> > +
> > +	iter = pci_slot_match_iterator_create(NULL);
> > +	/* Setup runtime pm for PCI root port */
> > +	__igt_pm_setup_pci_card_runtime_pm(pci_dev, i++);
> > +	while ((dev = pci_device_next(iter)) != NULL) {
> > +		if (dev->bus >= secondary && dev->bus <= subordinate)
> > +			__igt_pm_setup_pci_card_runtime_pm(dev, i++);
> > +	}
> > +}
> > +
> > +static void igt_pm_restore_pci_dev_runtime_pm(struct pci_device
> > +*pci_dev, char *control, int len) {
> > +	char name[PATH_MAX];
> > +	int fd;
> > +
> > +	igt_debug("Restoring runtime power management for PCI
> '%04x:%02x:%02x.%01x' '%s'\n",
> > +		  pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func,
> > +control);
> > +
> > +	snprintf(name, PATH_MAX,
> "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/power/control",
> > +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
> > +
> > +	fd = open(name, O_WRONLY);
> > +	igt_assert_f(fd >= 0, "Can't open control\n");
> > +
> > +	igt_assert(write(fd, control, len) == len);
> > +	close(fd);
> > +}
> > +
> > +/**
> > + * igt_pm_restore_pci_card_runtime_pm:
> > + * @pci_dev: root port pci_dev.
> > + * Restore power control attribute for all PCI endpoints devices for
> > +a given
> > + * root port.
> > + */
> > +void igt_pm_restore_pci_card_runtime_pm(void)
> > +{
> > +	int i = 0;
> > +
> > +	for (i = 0; i < MAX_PCI_DEVICES; i++) {
> > +		if (!__igt_pm_pci_control[i].pci_dev)
> > +			break;
> > +
> > +
> 	igt_pm_restore_pci_dev_runtime_pm(__igt_pm_pci_control[i].pci_dev,
> > +
> __igt_pm_pci_control[i].control,
> > +
> sizeof(__igt_pm_pci_control[i].control));
> > +	}
> > +
> > +	memset(__igt_pm_pci_control, 0, sizeof(__igt_pm_pci_control));
> > +	pci_system_cleanup();
> > +}
> > +
> > +static void igt_pm_print_pci_dev_runtime_status(struct pci_device
> > +*pci_dev) {
> > +	char name[PATH_MAX], runtime_status[64];
> > +	int fd, n_read;
> > +
> > +	snprintf(name, PATH_MAX,
> "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/power/runtime_status",
> > +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
> > +
> > +	fd = open(name, O_RDONLY);
> > +	igt_assert_f(fd >= 0, "Can't open runtime_status\n");
> > +
> > +	n_read = read(fd, runtime_status, sizeof(runtime_status) - 1);
> > +	igt_assert(n_read >= 0);
> > +	runtime_status[n_read] = '\0';
> > +	igt_info("runtime suspend status for PCI '%04x:%02x:%02x.%01x' %s\n",
> > +		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func,
> runtime_status);
> > +	close(fd);
> > +}
> > +
> > +/**
> > + * igt_pm_print_pci_card_runtime_status:
> > + * @pci_dev: root port pci_dev.
> > + * Print runtime suspend status for all PCI endpoints devices for a
> > +given
> > + * root port.
> > + */
> > +void igt_pm_print_pci_card_runtime_status(void)
> > +{
> > +	int i = 0;
> > +
> > +	for (i = 0; i < MAX_PCI_DEVICES; i++) {
> > +		if (!__igt_pm_pci_control[i].pci_dev)
> > +			break;
> > +
> > +
> 	igt_pm_print_pci_dev_runtime_status(__igt_pm_pci_control[i].pci_dev)
> ;
> > +	}
> > +}
> > diff --git a/lib/igt_pm.h b/lib/igt_pm.h index 162d3ca3c..a5a9c4760
> > 100644
> > --- a/lib/igt_pm.h
> > +++ b/lib/igt_pm.h
> > @@ -46,6 +46,21 @@ enum igt_runtime_pm_status {
> >  	IGT_RUNTIME_PM_STATUS_UNKNOWN,
> >  };
> >
> > +/* PCI ACPI firmware node real state */ enum igt_acpi_d_state {
> > +	IGT_ACPI_D0,
> > +	IGT_ACPI_D1,
> > +	IGT_ACPI_D2,
> > +	IGT_ACPI_D3Hot,
> > +	IGT_ACPI_D3Cold,
> > +	IGT_ACPI_UNKNOWN_STATE,
> > +};
> > +
> > +struct	igt_pm_pci_dev_control {
> > +	struct pci_device *pci_dev;
> > +	char control[64];
> > +};
> > +
> >  bool igt_setup_runtime_pm(int device);  void
> > igt_disable_runtime_pm(void);  void igt_restore_runtime_pm(void); @@
> > -54,5 +69,11 @@ bool igt_wait_for_pm_status(enum igt_runtime_pm_status
> > status);  bool igt_pm_dmc_loaded(int debugfs);  bool
> > igt_pm_pc8_plus_residencies_enabled(int msr_fd);  bool
> > i915_output_is_lpsp_capable(int drm_fd, igt_output_t *output);
> > +bool igt_pm_acpi_d3cold_supported(struct pci_device *pci_dev); enum
> > +igt_acpi_d_state igt_pm_get_acpi_real_d_state(struct pci_device
> > +*pci_dev); void igt_pm_setup_pci_card_runtime_pm(struct pci_device
> > +*pci_dev); void igt_pm_restore_pci_card_runtime_pm(void);
> > +void igt_pm_print_pci_card_runtime_status(void);
> >
> >  #endif /* IGT_PM_H */
> > --
> > 2.26.2
> >